segunda-feira, 23 de fevereiro de 2015

CLAUDIO COSTA: PHILOSOPHICAL TEXTS (TEXTOS DE FILOSOFIA)



DEAR READER!
THE AIM OF THIS 'BLOG' IS TO MAKE MY WORK IN PHILOSOPHY MORE ACCESSIBLE.
THERE ARE APPROXIMATELY 90 TEXTS, MOST OF THEM IN DRAFT FORM.
PAPERS WITH SOME INTEREST FOR THE PHILOSOPHICAL RESEARCH ARE MARKED WITH ONE OR MORE #.
COMMENTS AND OBJECTIONS WILL BE WELCOME!

PREZADO LEITOR! O OBJETIVO DESSE 'BLOG' É TORNAR MEUS TRABALHOS EM FILOSOFIA MAIS FACILMENTE ACESSÍVEIS. HÁ CERCA DE 90 TEXTOS, EM GERAL EM FORMA DE ESBOÇO. INTRODUÇÕES SÃO INDICADAS. TRABALHOS DE INTERESSE PARA EM TERMOS DE PESQUISA SÃO MARCADOS COM UM OU MAIS '#'. COMENTÁRIOS E OBJEÇÕES SERÃO BEM VINDOS!




ABOUT ME:

I am a CNPq researcher and full professor of philosophy at the UFRN (Brazil).
E-mail for contact: ruvstof@gmail.com

I made my M.S. in philosophy at the IFCS (Rio de Janeiro, 1982, with Raul Landin). Ph.D. at the University of Konstanz (1990 with Friedrich Kambartel and Gottfried Gabriel). Sabbatical stages of one year as a visiting scholar in the Hochschule für Philosophie, Muenchen (1995) (with Friedo Ricken), University of California at Berkeley (1999) (with John Searle), University of Oxford (2004) (with Richard Swinburne) and University of Konstanz (2009-10) (with Wolfgang Spohn).

AREAS OF INTEREST: All the central problems of philosophy.

MAIN PUBLISHED WORK: The Philosophical Inquiry (UPA: Langham 2002), "Free Will and the Soft Constraints of Reason" (Ratio 2006), "The Sceptical Deal with our Concept of External Reality" (Abstracta 2009), "A Perspectival Definition of Knowledge" (Ratio 2010), and "A Metadescriptivist Theory of Proper Names" (Ratio 2011); a corrected version of the ideas of the last paper are here presented under the title "Outline of a Theory of Proper Names". The best selection of papers in portuguese is Paisagens Conceituais (Rio de Janeiro: Tempo Brasileiro 2012). A selection of papers published in English containing improved versions of the papers cited above is the book Lines of Thought: Rethinking Philosophical Assumptions (Newcastle upon Tyne: Cambridge Scholars Publishing, 2014).


CURRENT RESEARCH: I am presently working in a book to be called Philosophical Semantics I: Building upon Wittgenstein and Frege. One of my aims is an attempt to reestablish the credibility of the internalist and cognitivist-descriptivist tradition concerning theories of reference. I believe that this can be done if we reconstruct the old theories in more sophisticated ways, able to solve the important challenges presented by Kripke, Donnellan, Putnam, Kaplan and others.






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ANÚNCIO DO LIVRO "VIDA EM PENSAMENTO"

O livro "Vida em pensamento: autobiografia filosófica", baseado em um Memorial de concurso, foi considerado para publicação por se tratar de uma introdução opiniosa a uma ampla variedade de tópicos da filosofia contemporânea. Ele será acessível sob forma de e-book a partir de março de 2015.







sábado, 14 de fevereiro de 2015

#TOWARDS AN UNIFIED THEORY OF TRUTH (draft on the correspondence theory of truth)

ATTENTION: THIS IS A ROUGH UNCORRECTED DRAFT. The final version will be published as the chapter 5 of the book Philosophical Semantics...  






TOWARDS AN UNIFIED THEORY OF TRUTH


We have got some conclusions from the last chapters: the epistemic meaning of a statement is its rule of verification, which is the same as a thought or (more precisely) an f-thought, the truth-maker of the thought is the fact stated by the statement; the effective applicability of the rule of verification or thought is the existence of the fact stated by it. We also saw that the thought – the rule of verification – when effectively applicable, is true. Maybe we should conclude from this that the truth of this rule or thought is the same as its effective applicability, so that the truth would be the same as the property of existence of a fact. Indeed, it is beyond doubt that the assertion of the truth of a thought is equivalent to the assertion of the existence of a fact. But equivalence is not the same as the identity: truth and existence may be distinct concepts, even if they are equivalent properties of thoughts.
   There is another reason to question a supposed identity between the truth of a thought and the existence of a fact, namely, the vague truism that we can find even in the dictionaries, according to which truth (in association with statements) is the property of being in accord with the way things actually are (facts). If our first methodological principle, according to which we should at least prima facie accept our commonsensical and ordinary language views, then the correspondence theory of truth must be the most correct one. However, is this identification of truth with the property of being in accord with facts sufficient to lead us to reject that truth is the effective applicability of the verification rule or thought?
   We can show that the two concepts are more than equivalent making a comparison with what we can say of the concept of the existence of a property designated by a concept. Suppose that we say that the property of a concept of being effectively applicable is not only its property of existence, but also its property of being in accord with the property designated by it, the property to which it is effectively applicable. Here the difference is only linguistic. But if we can by parity apply the same reasoning to the case of a thought or a rule of verification, we will conclude that the existence of a fact = the effective applicability of the rule of verification or thought = the truth of this thought.
   Anyway, if we wish to get a more feasible result, a good approach could be to reconsider in some detail the correspondence theory of truth.

Truth as correspondence
Some would think that the adoption of the verificationism means the abandonment of the view that truth is the correspondence between a statement and a fact. As we saw, a statement can be verified in many different ways, as far as it satisfies a multiplicity of different criterial configurations, while the fact corresponding to the true statement must remain univocally related to it as being one and the same. Consequently, according to the kind of verificationism we have proposed, it does not seem possible that what verifies the statement is a fact.
   My view is that this is a treacherous reasoning, and that we come to this conclusion only because we are searching for correspondence in the wrong place. As we will see, usually the correspondence is not between the thought and the many diverse criterial configurations usually given in sense-perception and able to verify it, but between the content of a thought and a fact (we could say the content of a fact), also apprehended by us, though this apprehension is usually the inferential result of one or the other criterial configuration usually given to us in sense-perception.
   In order to make this suggestion clearer, I need to develop what I believe to be the most adequate and comprehensive form of correspondence theory of truth, which ultimately requires a pragmatic investigation of the dynamic constitution of truth as correspondence. First, however, we need to make clear the structure of the relation of truth as correspondence.

The structure of correspondence
Assuming that truth is the correspondence or agreement between the thought and the fact referred by the thought, we need first to have clear each term of this formula. The thought must be the f-thought (even if it is inherently conceived by means of p-thoughts) expressed by a statement, which is also, as we already saw, the truth-bearer. The fact or factual content is what we have analyzed as the reference or correlate of the thought, its truth-maker in the most proper sense. And the correspondence should be seen at least as a kind of structural isomorphism between both – the thought-content and the factual content – in the sense of a biunivocal relation between the concatenated components of both.
   Assuming this nearly standard understanding of the correspondence, we can produce an identification between truth and correspondence in which the predicate ‘…is true’ is identified with the predicate ‘…it corresponds with the fact’, an identification in which both predicates work as semantically meta-linguistic predicates applicable to thought-contents, in a way similar to the way in which we say ‘“Themistocles won the battle of Salamis” is a historical statement’. According to this view, for any thought or content of belief p, to say that p is true is the same as to say that p corresponds to a fact. We can express this symbolically using p as the expression of an f-thought, V for the predicate ‘is true’, and C for the predicate ‘... corresponds to a fact’. The predicates V and C apply to p as meta-predicates belonging to a semantic metalanguage referring to the thought-content expressed by p, what can be shown by putting p under quotation marks. Here is the formulation:

(1)  Vp’ = Cp[1]

According to this identification, truth is the property of a thought-content expressed by a sentence p, namely, the property of corresponding with a fact.
   This formulation depends on the application of monadic predicates ‘...is truth’ and ‘...corresponds to a fact’. However, monadic predicates like ‘…is true’, as much as ‘…corresponds to a fact’, can be unfolded as dyadic predicates of a semantic meta-language relating the thought expressed by p with the fact or factual content that q like ‘…is true for…’ and ‘…corresponds to the fact that…’ In a similar way, we could say ‘“Themistocles won the battle of Salamis” express the same historical occurrence as “Themistokles gewann die Schlacht von Salamis”’.
   This means that the definition above can be explained more thoroughly as stating that for a given thought-content p, to tell that p is true for the factual content q is the same as to tell that the thought of p corresponds to or is adequate to the fact of q, understanding correspondence as a relation of identity of contents expressed by p and q, so that we can say that p = q. Giving a simple observational example: suppose that the thought expressed by ‘The Moon is white’ is true. We do it because of the factual content that the Moon is white. And this is the same as saying that the thought-content expressed by ‘The Moon is white’ corresponds to the content of the observation that the Moon is white, which is factual.
   Now, using the symbol V in the place of the semantically metalinguistic predicate ‘…is true for the fact that...’ and using the symbol C for the also semantically metalinguistic predicate ‘...corresponds to the fact that…’, we have the following formalized version of a more complete definition, in which the thought-content expressed by p and the factual content expressed by q are being metalinguistically related by the meta-predicates V and C:

(2)  ‘p’V‘q’ = ‘pCq

   Indeed, if (2) is an unpacking of (1), this seems to be the right way to formulate it. According to the identification (2), the assignment of truth is the same thing as the assignment of the relational property of correspondence, that is, the exact similarity of the thought-content with the factual content – a similarity of content that, we suppose, could be analysed in terms of structural isomorphism.
   Finally, we need to remember that according to the results of chapter 4, the f-thoughts are rules of verification. If it is so, to say that a content of thought corresponds to a factual content is the same as to say that a rule of verification (the f-thought) corresponds to a certain fact. But how could a rule of verification ‘correspond’ to a fact, except by being effectively applicable to a certain fact? Except by being satisfied by a fact? It seems also that for a rule of verification (a f-thought) being true it must be effectively applicable to its required fact. Hence, it seems that we can replace ‘correspondence’ with ‘effective applicability’ symbolized as A, and say that a rule of verification is true when it is effectively applicable to the fact, so that:

(3) V‘p’ = C‘q’ = A‘p’

   Moreover,  identifying correspondence with verification we can also say that for a given content p, to say that p is true or corresponds with a factual content q is the same as to say that p is verified by the factual content q. Calling ‘…is effectively applied to the factual content…’ ‘A’ again, we can say:

(4) ‘p’V‘q’ = ‘p’C‘q’ = ‘p’A‘q’

   Identifications (1), (2), (3) and (4) lay down structural relations explaining how truth can be theoretically equated with correspondence in the first two cases and with verification in the last one.
   However, as we will see later, we can add to them a dynamic dimension that seems ultimately indispensable, though often unnoticed.

Paradoxes of self-referentiality
Although limited, the identifications we have made already enable us to deal with paradoxes of self-referentiality. They preserve the analogy between existence and truth: in the same way as the existence is a property of concepts, truth or correspondence is a property of thought-contents or f-thoughts or propositions expressed by entire statements. Because of this, sentences like ‘“2 + 3 = 5” is a true statement’ and ‘“2 + 3 = 6” isn’t a true statement’ are grammatically correct and express correct attributions of truth, while self-referencial sentences like:

   This statement is true,
   This statement isn’t true,

aren’t grammatically correct and cannot correctly attribute a truth-value to a thought. One cannot say that they are wrong because they are self-referential, for there are self-referential sentences that have truth-value as ‘This statement has five words’. The problem is that, since the attribution of a truth-value, being a meta-predicate, isn’t a constituent of a thought, this attribution cannot belong to a content of thought in the same level the thought-constituents. The same applies to indirectly self-referent statements like:

   The next statement is false… The previous statement is false.

   In this case we try to apply the predication of a truth-value indirectly to the same statement we began by making through it a second statement - that says that the first statement is false – false. But in this case if the first statement is true it must be false and if it is false it must be true. The paradox is again generated by the fact that the predication of falsity is a constituent of the statements, which are indirectly self-referential instead of meta-predicative. The circularity results from the fact that truth cannot play a role as a constituent of a thought-content in the same level as the others: truth is a meta-property of a complete thought-content, not a property of it. It is, one could say, an external, not an internal property of a thought-content. Indeed the effective applicability of a rule of verification isn’t any internal property of this rule, but something that is added to the rule being independent of it.

The pragmatics of the correspondence relation
According to the view I wish to defend here, which is influenced by Edmund Husserl[2] and by Moritz Schlick’s short defence of the correspondence theory of truth,[3] the correspondence has a pragmatic side that deserves to be explored. Very often we can establish an idealized sequence with three successive temporal steps: (1) a suppositional, (2) an evidencial and (3) a conclusive step. Together they form a very common form of verificational procedure.
   The best way to explain this is beginning with a very simple example. Suppose that I ask myself: ‘Will it rain in Natal tomorrow?’ This was the suppositional step. Now, imagine that tomorrow comes and I go out of my home and I see that it is really raining. This is the second, procedural step. Once I do this, I compare my earlier question with the observational evidence that it is raining, and I conclude that the content of the question is the same as the content of my observation and that, therefore, they agree, they correspond. And this is something that can be meant with my judgment that it is indeed true that it is raining. Certainly, I could make this question tomorrow, as a hypothesis, soon after hearing some drops of water on my cellar, or I could have seen the weather forecast today telling that (probably) would rain in Natal tomorrow.
   Examples like this can be multiplied. A student has hear that another student, who isn’t very applied, has achieved a better result; he doubt this; then he asks the teacher if this was the case (the teacher has here a testimonial function). A notice is transmit in the TV informing that a nuclear test was made in some place of the earth… and this information is later confirmed by the responsible authorities (again a case of testimony). A similar procedure, as we will see, applies also to non-observational truths. But for now, restricting myself to perceptual judgments, I can say that at least for many cases we can formulate the following action’s schema with four steps:

1)    The suppositional moment: the realization of a supposition, hypothesis, conjecture, guess. In this moment, we ask ourselves whether an f-thought is true, if the rule of verification that constitutes it is effectively applicable. We can express this as ‘I suppose that p’ or ‘it is possible that p’, where p expresses a content that can be perceived. This step can be formalized as ‘?p’. This supposition is made within some linguistic practice, some context.
2)    What follows is the evidential or perceptual (or procedural) moment: realization of perceptual experience, under determined circumstances of observation, which has the potential of corresponding to the content of the supposition.
This is the way by means of which we try to verify the truth of the supposition finding its perceptual correlative; in the case of observational truths this step is very simple. We look for an expected adequate thought-content that, in an adequate context, we simply accept as a truth-maker, which can be rendered as ‘I have the perception of p’, call it ‘!o’ (phenomenalists call it registration or fulfilment). As we will see, there is no question about the truth-value of o: It is not an ‘evidence’ or ‘certainty’ in itself, but it is stipulated as such by means of the context or practice or language-game or linguistic system or practice in which it occurs.
3)    Confrontational moment:  comparison or confront between the suppositional content and the perceptual experience, what will allow the verification or falsification of the content of the supposition.
Here we ask whether the supposition matches the evidential result of the procedural step. In the case of perceptual experience that we are considering, we ask ourselves whether the thought-content of the hypothesis is like the thought-content given to us. Being both sufficiently congruent, this means that there is an agreement between both. In the case of a perceptual experience the positive answer can be summarized as p = o. It can also be that the thought-content expressed by the hypothesis shows to be different from the factual content given in the contextually expected sense experience. In this case: p o. In the practice it is possible that more than one perceptual experience is carried out, and in more than one way, but we are considering the minimal conditions.
4)    Judgemental result: Finally, in the case in which p = o, the thought expressed in the supposition will be accepted as true, otherwise false. When p = o, there is correspondence and the conclusion is an affirmative judgement that can be symbolized as ├p. In the case in which p ≠ o, that is, when there is no correspondence, the thought is false, what can be expressed be the judgement symbolized as ├~p.

We can summarize these four moments of the whole verification process regarding the achievement of observational truths of the kind considered above in the following temporal sequence:

?p, !o, p = o,├p

This analysis shows that correspondence does not occur directly between a perceptual statement and the reality, but usually between some suppositional thought-content and some perceptual content that is stipulated by the context of the linguistic practice as beyond doubt.
   It is also important to note that the standard state of a judgment├p has the form of a report that is settled and rested. However, it can be always questioned again. In this case, new verifying procedures can reconfirm the judgment or detect some inadequacy.    
   What we presented is what we may call an anterograde way to get the truth, since we go here temporally from the hypothesis to the observational evidence that confirms the hypothesis by being identical to it. However, the opposite direction is also possible. We can also have a truth resulting from the perceptual experience or observation, progressing from the evidence to the hypothesis – a way to achieve truth that we may call retrograde.[4] For example, open the door of my home with the intention to go out and unexpectedly see that it is raining. I come back to look for an umbrella with the obvious conclusion that it is raining. In this case the perceptual evidence comes first. But it seems that the recognition of truth does not belong to the perceptual experience as a direct product of it, since one can see the rain without taking account of it. I think that here we can explain the process of getting the truth included in the judgment of the given example in the following way. First we have the observational experience o! Then (still during or after it) we make the supposition ?p, which direct our minds to a certain interpretation of the experience. And finally we answer the supposition appealing to the evidence that has been given: we see that o = p. This is what brings me to the conclusion that it is true that it is raining. We could give to this process of retrograde achieving of truth the following sequential formulation:

!o, ?p, o = p, /├p

   The two cases we have considered until now are the simplest ones. The dynamic view of correspondence can be extended to the truth of non-observational, mediated thoughts. Suppose that Lucy is in the airport Charles de Gaulle in Paris, ready to take a flight to Dakar. The flight time is of approximately five hours. She calls her daughter, who lives in the savannah not far from Dakar, and asks her if the weather in the city is good; this is ?p. Suppose that she hears that the weather in Dakar will is and will remain good and warm enough. There is no significant reason for doubt this information, which she takes as giving her the appropriate evidence. The thought !q that she had when she asked about the weather there were good is the same as the thought belonging to the question ?p. Consequently, since p = q, she concludes that p is true, that the weather in Dakar is good. But the thought in !q is not an observational thought. It is the result of testimonial inferences that are unknown to her, based on the observation of the weather conditions in Dakar. In this case, putting ‘<<<’ in the place of some chain of reasoning unknown to her that leads to !q, and ‘!o’ to the observational thought(s) that in some way have originated !q (similar to those that she will have when she arrives in Dakar after some hours), we can formalize the verification process in which p is presently made true for her as:

?p, q! (!q <<< !o), p = q/p

Important to note is that the evidencial character of the observation !o is preserved in the supposed inferential chain, being transmit from thought to thought until the conclusion !q, which inherits its evidential character.
   The foregoing example is of anterograde verification, beginning with one hypothesis and ending with the comparison between hypothesis and a derived evidential f-thought. However, we also may have a retrograde procedure with a chain of reasons that ends with the match of a derived evidence with a supposition. Suppose that another person take the same fly and that the commander informs her that the weather in Dakar is and will remain good… The person will be brought to the conclusion that the weather in Dakar is in fact good by means of another indirect and for him unknown evidential chain. In this case it is the evidence that produces the question that is answered by means of a comparison of contents, from which the final judgment results that the weather in Dakar is good. This process can be summarized in the following sequence:

!q (!q <<< !o), ?p, q = p/p

We see again the difference between anterograde and retrograde verification. We may guess whether the intuitions of a researcher who still does not know how to proof some hypothesis, but has a glimpse in its truth, depends on the unconscious feeling that the !q is or may be derived from evidential observations or postulates.
   Also the general belief – universal and existential – can be explained in this way, as the identity between the contents of the hypotheses and the contents of sets formed by the respective conjunctions and disjunctions of factual contents, often resulting from inductive inferences based on observational facts. So, suppose that ├p is the assertion: ‘All the books in the shelf of my room are in English’. This generalization can be derived in a retrograde form from my observations o1, o2on, of each book in the shelf as follows:

{!o1 & !o2& !on } → !q, ?p, p = q /├ q

   Obviously, I can also first ask myself if all the books of my shelf are in English, and after looking each one of them to conclude that this hypothesis is true in an anterograde procedure:

?p, {!o1 & !o2& !on } → !q, q = p, /p

   As the former, this is a deductive generalization, but it is easy to see that inductive generalizations should also have not very different structures.
   There are other cases that I wish to give only an indicative solution. One of these is the case of auto-psychic truths. I know the truth that I have headache. One possibility: first, one learn interpersonally how to identify the location of pain, and by inductive exclusion the kind of feeling that one has when one has pain; this learning can be applied to pains in the head. Second, when one has the pain, there is a feeling of pain first: !s, and then !p, the thought that one would have pain, followed by the identification p = s, and the conclusion p.
    Finally, there are cases of true conditionals like the sentence ‘If you Peter were the president of USA, he would be famous’. Well, it is true that ‘All presidents of USA are famous’. Calling president P and famous F, we can state the same as {Pa1 -> Fa1, Pa2 -> Fa2… Pan -> Fan}. Now, there is a possible world where Peter is the president of USA. In this world it is a fact that Peter is the president of USA the sentence ‘Peter is president of USA’ true. Since in this world he is president of USA, he must be famous. But we conclude that Peter is famous because the sentence corresponds with the fact, even if it is not a fact in our world, but in a possible world, that is, a supposed fact in a supposed circumstance that we are able to imagine. Another curious case is of ethical imperatives like (i) ‘You should help the life of someone in danger, as far as this does not endangers your own life’. This seems correct. Now, how to explain correspondence? One answer could be the following: suppose that a consequentialist principle is (ii) ‘Whe should handle in order to do the better for all or at least the less bad for all’. It is correct because we consider a principle true if it increases the happiness of the society in general and this is the function of ethics and simply its criterion of correctness. But if we can derive (i) from (ii) and someone says (i) we see that it corresponds with (i) and we can say that it is also true and not only correct.
   Another point is that we have understood the f-thought as a rule of verification. How would all these f-thoughts as rules of verification fit with our schemas? This is a question that I will let to be considered later.

Generalization to formal sciences
Similar structural and dynamic forms can be found in the formal sciences, allowing us to generalize the correspondence theory to a domain traditionally occupied by the coherencial theories of truth. Suppose that we want to demonstrate that the sum of the angles of a triangle is 180°. We can do it first by suspecting that this could be the case: ?p. Then we search for a proof. We can trace a straight line that passes through one of the vertex of the triangle, so that this line is parallel to the side opposed to this vertex. Since the three justaposed angles formed by the parallel and the triangle are the same as the internal angles of the other two vertexes of the triangle plus the angle of the first vertex, and their sum is 180°, we conclude that the sum of the internal angles of one Euclidean triangle must be 180°. This conclusion is the evidence !q. Since we see that the content of !q is the same as the content of the hypothesis ?p, we conclude ├p. Using ‘a’ for axioms, the form of this procedure could be rendered as:

?p, !a>>>!q, p = q, /p

   This is an anterograde procedure.
   Now one example from the arithmetic: we can prove that ‘2 + 2 = 4’ in the Leibnizian manner. We begin with definitions (which correspond to basic perceptual experiences in empirical sciences). First, we define 2 as 1 + 1, 3 as 2 + 1, and 4 as 3 + 1. We call these definitions d. Replacing the numbers by the definiens, we get ‘(1 + 1) + (1 + 1) = (3 + 1)’. Since 3 was defined as 2 + 1, and 2 as 1 + 1, 3 can be replaced by (1 + 1) + 1. Replacing the 3 by this result we get: (1 + 1) + (1 + 1) = ((1 + 1) + 1) + 1), which proofs that 2 + 2 = 4. In this way we derive the confirmatory evidence of the hypothesis !q, which is ‘2 + 2 = 4’; this confirmatory evidence serves to check the hypothesis !p that 2 + 2 = 4. Again, abbreviating the definitions as ‘d’, we have the following anterograde verification:

?p, (!d>>>q),  p = q, /p

   We see again that the evidencial content of !q, which serves to check the hypothesis that ‘2 + 2 = 4’, is not the same as the definitions of 2, 3 or 4. It is the same as the result of a reasoning that we make from them, a reasoning that derives from the definitional character of its premisses.
   Finally, we can give examples concerning logic. Consider the following theorem of modal logic: ‘P → ◊P’. This can be seen as our hypothesis ?p. How to prove it? Using the S5 modal system we can do it making use of the axioms AS1, ‘◊ P ↔ ~□~P’ and AS3, ‘□~P → ~P’ as assumptions. With this and with the help of the rules of propositional logic, we construct the following proof of the theorem:

     The hypothesis is: ?p, where p = (P → ◊P)

     The proof:
1       □~P → ~P             (AS3) (taken as evidence)
2       ~~P → ~□~P         (1TRANS.)
3       P → ~□~P             (2DN)
4       ◊P ↔ ~□~P           (AS1) (taken as evidence)
5       ~□~P → ◊P           (4 ↔E)
6       P → ◊P                  (3,5 SD)

Nun, the result  P → ◊P = !q.
Since p = q, we conclude that p is true, we conclude ├p.

   Since the !q, which carries with itself the evidences derived from the axioms, expresses the same thought-content as the hypothesis ?p, we conclude that there is a correspondence, that p is true, that ├p. Also in this example the verificational reasoning has an anterograde form.
    Of course, the retrograde form could be also found regarding any of the three above exemplified cases. Considering the first case, suppose that someone draws a straight line that passes throught a vertex of a triangle, being this line parallel to the opposite side. This person could easily be lead to the conclusion that this triangle and in fact any triangle would have 180°. In this case we would have the following retrograde verificational procedure:

!a >>> !q, ?p, p = q, /p
I suppose that this could be the case when a mathematician or a logician has an insight of a certain theorem as true. The upshot is that the procedures whereby we show the correspondence of formal truths are structurally analog to the procedures whereby we show the correspondence of empirical truths.

Why analytic truths are called true?
Finally, we can apply a similar procedure for the so-called analytical sentences, showing that they are also called true because of correspondence, even if this is, as we will see, a limit-case. It is possible to say, for example, that the analytical statements ‘It is raining or it is not raining’ and ‘Singles are non-married’ are true because they correspond to the respective facts that necessarily either it is raining or not, and that no adult single man can be married. What entitles us to say this? Now, understanding the analytic propositions such as those that are true by means of a combination of the senses of their component expressions (pace Quine), consider how sentences such as hypotheses ?p1: ‘Is it raining or not?’, ?p2: ‘Are singles non-married?’. Here the verificacional relationship is not with the world outside the content of thought, but with a conventional derivation showing that the logical structure of those sentences is tautological. Thus, in the case of ?p1, which is already in this form, we realize right away that its structure is the same as !q1, which is the statement of the principle of excluded middle or ‘p ˅ ~ p’, which can be seen as a logical truth. This is enough to make !p1 true because, independently of the senses of the constituents of !p, one can see its logical structure as warranting its truth. Calling l something we accept as a logical truth, we can formulate this correspondence as follows:

?p1, !l !q, p1 = q1, /p

    As ?p2 (which means ‘Is every single non-married?’) is not already in the form examined, we need to bring it to this form before we see the match. To do this, we begin with the definition !d of single as ‘a non-married adult male’. Calling ‘male’ H, ‘adult’ A, and ‘non-married’ ~M, we can see that from !d we can derive !q: ‘All single are non-married’ as a tautology. Now, we have the following correspondence:

?p2, !d !q2, p2 = q2, /p
  
As we see that ?p2 has the same content as q2, which is derived from a truth by definition, we see that p2 must also be true.[5]

Coherence as an intermediator
Another interesting point regardig the proposed understanding of the correspondence is that it allows the absorption of the coherence theory of truth into the correspondence theory. Coherence can be understood simply as a procedure whereby the correspondence is obtained. The modal proof above does not come directly from AS1 and AS3, plus some rules of propositional logic, to ‘P → ◊P’. We use inferencial steps, and these steps are what constitute the coherence, which is often erroneously considered the proper criterion of truth in formal sciences. In the present case coherence is constituted by material implications, but it includes inductive inferences in the case of the verification of empirical thoughts.
   To illustrate the latter case I will consider two examples. First, suppose that a gift is anonimously sent to me. I open it and see that it is the book The Cloven Viscount, from Italo Calvino. I wonder if Silvia has sent it. I know that I presented Silvia with a copy of the book The Invisible Cities by the same autor and that she told me than that the The Cloven Viscount was a funny book. But Silvia lives in Rom and the present was sent from Rio de Janeiro. So I realize that this book could have been sent from somewhere else. But then I remember that Silvia could be back in Rio de Janeiro, a city where she lived most of her life. An advocate of coherence theory of truth would say that the proposition p ‘My friend Sylvia sent me a copy of the Cloven Viscount’ is made true by its consistency with other propositions like r = ‘I gave an exemplar of The Invisible Cities for Silvia’, s = ‘Silvia told me that The Cloven Viscount is a funny book’, t = ‘Silvia’s gift could have been sent from Rio de Janeiro’. The belief in p is true because it is consistent with the beliefs r, s and t.
   However, what we really have here is an indirect procedure of verification of the correspondence via coherence. I can assume that I have started with the hypothesis ?p. The beliefs r, s and t together make inductively probable the conclusion !q, namely, ‘Sylvia has sent me an exemplar of The Cloven Viscount’. But since I see that p = q in content, I am allowed to conclude that the thought expressed by p corresponds to the thought expressed by q, namely, that p expresses a true f-thought, that p. But it is important to note that this conclusion is due to the consistency of p with the propositions r, s and t, that is, r & s & t make q probable, what makes me to conclude the thought expressed by ?p corresponds to the reality expressed by !q. It is curious but important to note that the second term of the correspondence is in these cases, as in the most ones, not an observation, but the result of a chain of reasoning grounded in the observation.
   Now we could ask what comes first: correspondence or coherence? Is the coherence dependent on the correspondence or, on the contrary, the correspondence is dependent on the coherence, as coherentists would prefer. The answer is that coherence would be independent of correspondence at least if thought-contents could get their probability independently from any observation. But this is not the case. The thought-contents expressed by r, s and t either describe observational propositions or are based on them, for example, r is something that Silvia gave to me personly. They should have more directly to do with the correspondence with the empirically observed factual contents. And they are the ones who guarantee to me q as derived evidence and not the other way around. This guarantee of q, in turn, is what makes the thought of p true for me. Coherence would have no force if it weren’t at some point grounded on observational propositions, in the case of empirical truths, and on axioms or postulates, in the case of formal truths. Indeed, any fairy tail can be coherent and it will not gain any truth with the increase of coherence, since it is not grounded in any evidential fact.
   A second example concerns the veredict of a judge. It is often coherencial, since crime can be only rarelly receive direct testimony. The following example teaches us something important about the limits of coherencial theory and its relationship with the correspondencial theory. Shortly after his marriage with Ms. Rose, the American pastor David was interned into a hospital with severe abdominal pain. Since the exams have shown a high amount of arsenium in the blod of reverend David, which we abbreviate as r, the following question was posed: ?p = ‘Tried Ms. Rose to poison Reverend David?’. This supposition was later confirmed by the following further evidences:

s: Mrs. Rose had the habit of preparing soups for her husband, taking them even to the hospital.
    t: Traces of arsenic were found in the pantry of Rose’s hause.
u: The bodies of the first three husbands of Ms. Rose, with have been all died from unknown causes, were exhumed, with the surprising discovery of a large amount of arsenic in their hairs.

We can now build the following verificational process:

!r, !r > ?p, {!r & !s & !t & !u} > !q, p = q, /p

   Certainly, the statement p is made true by its consistency with the statements r, s, t, and u. But a crucial point to be noticed is that the statements r, s, t, and u are all made true by corresponding to evidencial factual contents publicly observed. Now, what this suggests is that the coerencial view of truth cannot stand alone. The plausibility of q is grounded in the conjunction of the observational statements r, s, t and u; and they are true because of their correspondence with observational contents, even if they also have theoretical assumptions. Coherence cannot originate truth, even because implication and induction, the two central forms of coherencial relation, are defined as ways of preserving truth, begging in this way the question. Hence, coherence works only like the wires of an electric power grid: though they do not generate the energy, they are able to transfer it. We see that coherence is not an independent mechanism, but only a interdoxal mechanism by means of which the correspondence is made. Coherence transfers the truth-force generated by the correspondence of contents of more basic beliefs to the derived evidences acting in the interior of the belief system in order to produce the content of thought expressed by q, which is accepted by us as evidential, corresponding with the proposition p when having the same content, what means the same as making p true. This is why we also can say that the statement p is true because it corresponds to the fact that Ms. Rose has poisoned the Reverend, but that we know about this fact indirectly, from the consistency of the hypothesis with other contents that correspond with the facts that have been observed by us. This thought q, we could say, also expresses what we are sure to be a fact, namely, the fact that Ms. Rose tried to poison reverend David. It is by being involved in the correspondence that coherence is involved with truth; consistency is just an interdoxal mechanism by which correspondence takes place.

What about the truth of the truth-maker?
One of the most serious problems for the correspondence theory of truth concerns the infinite regress that treats the evidences that verify the hypotheses. We can pose it in the form of a dilemma: Either the evidential content can be doubt or not. If not, it seems that we fall into dogmatism; normal sensory and perceptual truths are beyond any possibility of being false. But this would not be in conformity with the fallibility of our experience; we cannot be absolutely sure about the evidence of any empirical contents. Now, if the evidential content can be doubted, it seems that we need to look for a new evidential content, identical to what we have considered, which would warrant its truth; but, since this new content isn’t also beyond doubt, it should also be warranted, and so indefinitely. If this regression cannot be stopped, we have no way to ground our supposed truths.
   I think that the answer to this dilemma can be found when we consider examples in sufficient detail. Consider the following example of an observational sentence o: ‘There’s a dolphin swimming in the sea’. The truth of this sentence depends on the observation of a Dolphin coming on the water from time to time, an observation that can be interpersonal. The procedure has the form:

!o, ?p, p = o /├p.

But this does not mean that o, the given evidence, is absolutely warranted. It can be defeated. Suppose, for example, that in order to entertain the tourists, a diver swims with a rubber dolphin stuck on his back, coming up from time to time in order to produce in the bathers the illusion that they are seeing a dolphin. In this case the evidential content !o that should ground the verification of ?p will turn to be simply false.
   However, the answer of the problem isn’t difficult. An evidential content doesn’t need to be absolute because it is always postulated as evidence under some context or practice or language-game that presupposes appropriate circumstances. Thus, under appropriated circumstances, given in a practice that we may call A, we postulate that the observational content ‘I am seeing a dolphin that just emerged from the water’ is an unquestionable evidence expressed by !o, where people are looking the see from the beach during the day… In this practice, seeing a dolphin is undoubtedly accepted as the truth-maker of the hypothesis ?p. Since o has also an internal phenomenal content, we could say that in this case the postulation is that the content of o (‘We are having the experience of seeing a dolphin emerging from the water’) can be seen as the same as the state of affairs given in the world (‘A dolphin has just emerged from the water’). But this practice assumes normal background circumstances, namely, that all other things remain as we assume that they are. However, we can imagine contexts or practices in which the circumstances these expected circumstances are defeated. Thus, suppose that there is no real dolphin, and that a diver swims under water with a rubber dolphin stuck in his back, in order to give the tourists the impression that there are seeing a dolphin… What we have here is a different language-game, a practice B, with very different background circumstances, in which experiencing the sole vision of a dolphin emerging from the water cannot be postulated as the same as seeing a dolphin anymore. Under the circumstances posed by a language-game in which there are rubber dolphins being cared under water, to observe a real dolphin would certainly require a close and more much careful examination, for example, an underwater inspection that we could call o’ and that would be postulated as the evidence in the circumstances of B. In this practice, seeing a true dolphin in order to verify the proposition p could be formulated as:

!o’, ?p, p = o’ /├p.

   We see that the evidence is postulated as absolute, but only relatively to some context, to some practice, to some language-game that only works assuming some usual background of circumstances. If we get the information of a different background of circumstances able to suspend the assumed practice, the postulation of absoluteness, of evidence, of certainty, vanishes. In sum: what we call evidence is context-relative.
   Another similar example can make the point still clearer. A person is in a desert and she is victim of mirages. Firstly she believes that the lake that she sees in the horizon is real. But soon she sees that it is a mirage caused by unusual atmosphere circumstances. These unusual circumstances invalidate our usual interpretation of sensible content. The normal background circumstances BC are here being replaced by unusual circumstances of non-adequation BC’. The person has learned that the unusual circumstances invalidate the rules of the usual language-game, so that instead of saying ‘I see a lacke in the horizon’ the person says ‘I see the sky reflected in the horizon’. What was evidence is false and replaced by a new evidence, which is that of the sky reflected in the horizon. It is important to note that the content of perception in both cases is the same. But the interpretation we give to this content is very different, and it is different because of the different surrounding circumstances that forms the background information necessary to the decision of what counts as evidential content.

The objection of a linguistic circle
Perhaps the most important objection regarding this matter is the so-called problem of the linguistic circle: propositions can only be compared with propositions, and by comparing hypothetical propositions with evidential contents, even if taken as certain, we would remain trapped inside of language; even if we find the strongest evidences, they would be inevitably intra-linguistic… Here again, we would be in danger to fall into a reduction to infinite, having as corollary epistemic scepticism
   A general remark against this objection is that in order to say that we are trapped into an intra-linguistic world of propositions we are already assuming that we know the existence of an extra-linguistic external world, what remains unexplained. Moreover, echoing Moritz Schlick’s view, A. J. Ayer gave to the objection of the intra-linguistic circle the following answer:

We break the circle by using our senses, by actually making the observations as a result of which we accept one statement and reject another. Of course we use the language to describe these observations. Facts do not figure in discourse except as true statements. But how could be expected that they should?[6]

Ayer’s argument constitutes in a strong appeal to common sense. Despite of this, it seems to contradict another persistent idea, which is also commonsensical, namely, that the content of the perceptual experience should be a belief-content, which is something mental from nature, what means that we would never have direct and unquestionable access to things related to observational thought – the facts as they are in themselves.
   One reaction to this argument would be to accept idealism. But idealism is a forbidden solution. Idealism defends that all reality is in some way or other mental; but the concept of mental is relative to its opposite, the concept of physical, in a similar way as the concept of above is relative to its opposite, the under, the earlier to the after, etc. If there is no under, there is no above, without the earlier we have no after, and in the same token if there is no physical, there is no mental altogether. If we take the normal language seriously, that is, if we remain on the side of our methodological principle of do not reject common sense truths without serious reason, idealism remains an anathema. So I prefer to preserve the opposition between the mental and the physical proposing that the contents of perception have some kind of Janus face. They can be seen in two ways, in a psychological or in a physicalist way, as follows:

(a)  In a psychological way the content of perception is interpreted as a sensory content internal to the mind, or,
(b) In a physicalist way the content of perception is interpreted as an observational content independent of ourselves (s-properties and their combinations).[7]

   In the psychological sense (a) the experiential contents are what we could call sensory contents. However, they can be also interpreted in a physicalist sense (b), as what we could call observational contents, that is, as s-properties and their combinations (or tropes or bundles of tropes).
   We can illustrate this duplicity in the interpretation of perceptual judgments comparing them with the duplicity of the objects that we see through a looking-glass. What we see in the looking-glass can be interpreted as a simple image of things, for example, of a vase of flowers. But it can also be seen as the vase of flowers in itself. I can, for example, point to the object through the looking glass and you can ask me if I am pointing to the real object or to its reflected image. The difference is given by the context: the image isn’t real; one cannot touch it, one can change its size by approaching the vase to the looking-glass, and the image is circumscribed into the looking-glass. The real vase of flowers, on the other hand, can be touched, its size will be seen as remaining always the same independently of the size of its image, and it will not be circumscribed into any frame. However, the visual internal relations between the image of the vase of flowers and the real vase of flowers will remain the same. 
   This suggestion is reinforced when we consider illusions in which the psychological content is disconnected from its physicalist counterpart. For example: when I put my index finger on the apex of my nose I see my finger duplicated, but I do not say that I see two fingers. Why? Because ‘seeing’ is a verb referring to what is really given in the world, what I called observational content. For this reason I can say that I see only one finger, though duplicated. My observational content is of only one finger. But at the same time I can say that I have the sensory experience or the visual images of two fingers. Now, if I rise my index finger in front of my eyes at the distance of 50 cm., the sensory content (the visual image) and the observational content collapse into the same one finger, they cannot be distinguished. Now I can say that I am experiencing the sensory content of one only finger and that I am simultaneously experiencing the observational content of one only and the same finger. I know this inductively, though I cannot distinguish them.
    Another, the most common case, regards not number, but distance and size. When I see a jetliner approaching to the airport, it seems at first small because it is very distant: the sensory content, that is, the sensory image is small. But I may insist in saying that what I see – the content of observation – is a big object that appears small because it is distant. The observational content can be said to be big, though it does differ from the sensory content, and the reason for this belongs to my physicalist interpretation of it. Now, after the jetliner lands, the sensory content or image is much bigger. I will say that now I am seeing the jet in its real size. And it is big when compared with smaller aircrafts and most artefacts of metal. Now the visual image, the sensory content matches in size the observational content. We have what is conventionally seen as the standard perspective for the comparative measure of size in the case in question.
   Applying this to our view of truth, when we wish to confirm a hypothesis, these experiential contents of perception are interpreted in the physicalist perspective (b), as observational contents. They are postulated – within a supposed linguistic practice – as evidential contents of observational experiences or truth-makers. However, when the linguistic practice is rejected because of some unexpected contextual elemente, as in the case of the rubber dolphin considered in our example, then the same content is able to be interpreted only in the (a) sense, as a mere visual image suggestive of something that does not really exists. This explains why our observational findings may follow a foundational cognitive rule and at the same time remains fallible.
   The next important question concerns the general criteria that allow us to distinguish between the psychological and the physicalist interpretations of the contents of perception. We are in need of establishing criteria that enable us to distinguish those contents of thought that we are able to project in the external reality. Here our reflexions about Mill’s phenomenalism in the last chapter come to the fore.

Criteria for attributing external reality to perceptual content
As we saw, when we discussed Berkeley’s and Mill’s phenomenalism, the sensations, even if they are only possible ones, are psychological, what leads us to the pitfalls of idealism regarding what is given to us in the perception. The only way to prevent this is to find criteria for an interpretation of what is given to the sensory experience (the contents of perception from the perspective (b)) that enables us to consider it as belonging to the external world, as s-properties (tropes). Mill, though confusing the object (matter) with its existence (the permanent possibilities of sensations), instead of considering it what as kind of content of perception whose experience is (while it exists) permanently possible, wrote that these possibilities (as matter) are objective, that is, since they belong to an intersubjectively accessible public world, while the sensations in themselves remain inevitably subjective. Mill also noted that his possibilities of sensation would follow regularities of nature, like the causal laws of physics, and that they are independent of our will, which are typical of matter.
   We can do better than Mill. We know that the permanent possibilities of sensations can be approximated to existence, but not with matter, because different matters (that is, different substances, material things) differs one another in different ways, while existence is always the same, namely, the property of matter (I would say, of material things) of existing. Moreover, we proposed that the contents of perception can be not only subjectively interpreted – as psychological contents – but also objectively interpreted – as s-properties or tropes. Indeed, what Mill noted, the permanent possibility of sensations, the objectivity (intersubjectivity), the following of regularities, the independency of will, are all criteria for the existence or reality of external things. This means that these properties can be taken as criteria for the interpretation of the contents of sensation as belonging to the external world, that is, as s-properties our tropes: these properties and their sets (i) should be permanently accessible under adequate conditions( during some time, called the time of their existence), (ii) should be intersubjectively accessible, (iii) should follow follow regularities (primarily physical laws), (iv) should be independent of our will. These are indeed criteria of external reality that have been considered by several traditional philosophers as Locke, Berkeley, Hume, Kant, Frege and Moore. To this we could add (v) Berkeley’s and Hume’s suggestion that we could call an idea external when it enters with the greatest force in our soul (that is, which is given to our percepts in its maximal intensity). The analytic philosopher G.E. Moore has attempted to summarize these criteria of reality in a paper in the following passage:

The real is something independent of the mind that is verifiable by others, continuously connected with other things, and in this way has certain causes, effects and accompaniments (I would say that it ‘displays regularities’) with the highest degree of reality.[8]

    It is true that when considered in isolation these criteria do not warrant that contents of perception (seeing under the perspective (b)) are externally real. For example: a sensation can have the most intense degree of intensity and be hallucinatory, as in the alcoholic psychosis. And a very realist dream can be tediously conformed with the expected regularities of our physical and social reality. Moreover, a dream is usually independent of our will, though not always (as the lucid dreams). An even interpersonal agreement about states of affairs can occur, in the case of a collective hallucination. And external occurrences can be directly dependent of our will (in the case we have a brain-reader associated to our motor-cortex).
   However, this is not the point. There is a way in which these conditions can be transformed in a definitional criterion and in a sufficient condition for the ascription of reality in the most important sense of the word, which I call inherent. It is when we demand that these conditions are given all together for enough time. Thus, suppose that under normal circumstances I see my personal computer in front of me. I know that this complex group of contents of sensation is presented to me as a complex group of mental images and sensations. But I also know that I can consider  that this content is given to me as something external, since it is given in the most intense degree, since it is co-sensorially given (I can see and touch the personal computer), since I am (inductivelly) sure that other persons would agree that it is here in front of me (if they were here to see it), and since the machine follows the expected physical regularities, and since after a while it is clear that these sensations are permanently possible. All of this warrants to me that the personal computer I am seen is not an imaginary combination of contents of sensation, but a content of sensation that can be seen as a belonging to the real world around me. We can summarize contents of sensation that can be seen as externally real as those that satisfy the following criteria:

    DEFINITORY CRITERION OF EXTERNAL (INHERENT) REALITY:
A content of sensation can be seen as externally real (it can be interpreted in the sense (b))
Iff
(i) it is given to our senses in the most intense degree,
(ii) it is (normally) co-sensorially given,
(iii) it is (usually) independent of our will,
(iv) we are sure that it is potentially subject of intersubjective experience and agreement,
(v) it is permanently presentable to potentially intersubjective experience (they are owners of warranted and continuous possibility of sensations, using Mill’s words).

   On the other hand, purely psychological contents of perceptual thought, as much of imaginary sensory contents (as the hallucinatory ones), lack these properties in part or completely.
   I am not denying that in the cases of artificial reality or skeptical hypotheses this definitional criterion can be in part or even totally mimetized. But curiously enough, when it is totally mimetized, as in the case of a skeptical hypothesis (suppose that someone discover that he is a brain in a vat or that we are living in a machine of virtual reality or that the world is a dream) the (inherent, that is, typical) reality of what is experientially given in the skeptical hypothesis is not denied. These contents remain very real indeed, though not ultimately real. They are, we could say, inherently real, even if they are not adherently real, since they do not belong comparatively to the ultimate reality, but are a by-product of it. Though inherently real, they are non-real in the adherent sense, since they are the product of a world that relatively to them is not only inherently, but also adherently real. However, since the inherent sense of reality is our usual one, and we are not dealing directly with the problem of scepticism, this point is of few interest to our present concerns. [9]
   Finally, we should remember, perceptual contents understood in the sense (b) are s-properties (or tropes) given to us always perspectivally. And in themselves they can be understood as complexes of complexes of s-properties, that is, as hypercomplexes of s-properties. And the whole world can be understood as a hypercomplex of hypercomplexes of… complexes of s-properties. But it is better to stop this discussion here, since it is also not the aim of this book the development a fully argumented ontology of s-properties or tropes (see my views about this issue in Appendix IV).

Are we falling into the myth of the given?
One could ask if we are falling into Wilfrid Sellars famous myth of the given regarding what we call sensible and external content. The argument against the myth of the given can take the following form: (1) our beliefs regarding facts in the external world are only justified by the way they are given in the sense-experience; (2) sense experience (2a) isn’t part of the world and (2b) isn’t part of the products of our conceptual cognition like thoughts and beliefs; (3) from (1) and (2a) classical empiricists conclude that our knowledge of the world is inferred from sense experience; (4) since inferences derive knowledge from knowledge, sense-experience must be itself a form of knowledge. This is called the doctrine of the given. However, Sellars objects that (2b) is incompatible with (4), concluding that the doctrine of the given defended by the classical empiricism is a myth.[10]
   A first point to be noted is that when the content of experience is understood as an observational content, it is located outside the subject. So, to this case (2a) does not apply. Moreover, this content, as any other, is never considered alone, but always in the dependence of the context of a linguistic practice, what makes it very different from ‘the given’ targeted by Sellars. Moreover, even when we consider the experience psychologically as a sensory content, Sellar’s argument does not apply. The reason is that as far as the sensory content (supposedly ‘the given’) of the same or different kind are connected or unified, they are already of a conceptual nature, even if not of a linguistic-conceptual nature, since for the last case we would need to express this unity by means of a concept-word or some other linguistic expression. Consequently (2b) does not apply to our case too. Now, considering that sense experience can be itself conceptual, though non-linguistic, it is also a form of knowledge, what means that we can easily derive linguistically articulated knowledge from it. That this conclusion is true is made clear by the knowledge that we subscribe to animals that lack any language. Animals that lack a language must be able, for example, to recognize a prey or an enemy visually, and by doing this they must unify their visual sensory experience in the form of non-linguistic concepts.

Correspondence, verification, and intentionality (Husserl)
Now we can come back to our initial problem. We have two seemingly incongruent theses. The first is the thesis that truth has to do with the existence of the fact, that is, with the property of effective applicability of the verificational rule or f-thought. The second is that truth is correspondence, that is, the identity of content between ?p and !q, as explained above. However, are these not very different and maybe incompatible views?
   I think that I can bring some light to this problem reconsidering some of Edmund Husserl’s views on truth in his VI Logische Untersuchung. I believe that he has shown the path, even if in a tentative and confused way. As we saw, Frege spoke on senses or meanings, understanding them as abstract entities. Wittgenstein has suggested instead, according to our interpretation, something that leads us to the admission that the meaning is given by semantic rules or combinations of rules. Husserl, before Wittgenstein, has instead spoken of intentional acts as instantiating meanings, which should be for him, as for Frege and other German philosophers of the time, abstract entities. My take is that Husserl, Frege and Wittgenstein were all speaking about nearly the same thing, though from very different points of view. Fregean senses, as we saw, are semantic rules or combinations of rules. But the same applies to Husserl’s intentional acts: they are (in accordance with our view of the semantic as always psychologically instantiated) cognitive instantiations of semantic rules or combinations of rules. In other words: referential meanings (senses, informative or cognitive contents) are semantic rules or combinations of semantic rules that are cognitively instantiated in the form of mental acts directed to something, namely, intentional acts.  According to this view, intentional acts and the applications of semantic rules or of combinations of semantic rules are the same things expressed respectively in a cognitivist (psychological) and in a semanticist fashion.
   Having in mind this understanding, I will first present the essentials of Husserl’s theory of truth in the Logical Investigations. Afterwards I will translate his main ideas in our language and, finally, show how the insights we may get through this considerations can bring us to a possible solution to the problem of the relationship between semantic verificationism and the corerspondence theory of truth.
   According to Husserl’s view, the meaning of a linguistic expression is an abstract object like in Frege. But the meaning of an expression, of a sentence, can be instantiated in the form of a meaning-giving intentional act (a bedeutungsverleihend Akt), which abstracts its application in the reality or (in the case of a sentence) of its truth-value (for example, I think about my sunglass, I think that the sunglass is in the shublade). But we can go further and do an intentional act of meaning fulfillment (a bedeutungserfühlend Akt) related to the same expression or sentence (for example, I see my sunglass in the shoeblade). In this last case the object of the act is not only intended, but also given to us ‘in person’ according to Husserl. Finally, there is a third act, an act of synthesis, in which we make ourselves aware that the object intended in the meaning-giving intentional act is the same as the object given in the meaning-fulfilling intentional act. For Husserl, through this last act we achieve the awareness of the truth and in this way also knowledge. The truth, according to him, is correspondence in some internal sense, because it is the sameness of the object intended by the meaning-giving act with the object intended by the meaning-fulfilling act. As he writes, truth is ‘the complete agreement of what is intended with what is given as such.’[11] Admitting that there can be a diversity of perspectival acts of fulfilment summing in order to warrant our knowledge of the object, to give to the experience evidential force, he also writes:

When a presentative intention finds its last fulfilment, the genuine adequatio rei et intellectus is realized. The object is really presented as intentioned. So is the idea of all signitive fulfilment. The intellect is the intention of thought, the intention of meaning. The adequation is realized when the intentioned object in the strict sense is given to us as it is thought.[12]

   This is the summary of what seems to me Husserl’s chief insight on the nature of truth.[13]
   Now, if we read the meaning-giving and the meaning fulfilling intentional acts as psycho-semantic rules, and, for complete assertive sentences, as verificational psycho-semantic rules, we can make the following paraphrases of our view of the pragmatic of the correspondence relation:  If a thought-content is a verificational rule, then it seems that ?p expresses a verificational rule (or part of it) that is applied only in our minds, and that !q, which gives the evidence, expresses another verificational rule, which is applied to the reality, that is, to what satisfies our criteria of inherent reality. If these rules are exactly similar, the first rule, the thought that p, is true, otherwise not.
   Now, even if we agree that these two verificational rules must have exact similarity in order to warrant correspondence, what has this to do with the effective application of the verificational rule? Wouldn’t be more sensible to understand as a verificational rule the whole process of verification? For example, the process described in the following example concerning the poor husband of Ms. Rose:

!r, !r > ?p, {!r & !s & !t & !u} >>> !q, p = q/p

The only answer I can find is that here we have here two senses of the verification, in the first verification can be identified with the meaning of a proposition, but not in the second:

(a)      In the first sense the verificational rule considered separately from the correspondential procedure. This is the rule effectively applied in !q, whose application is only conceived in our minds in ?p. This is also the rule expressed by !q, which is exactly similar, though considered effectively applicable to the state of affairs in the reality. And this is also the case of the applied verificational rules !r, !s, !t and !u in the given example.
(b)       The second sense of verification is (b): that of the whole procedure of effective verification. It is important because this is the sense in which verification can be equated with correspondence. When we speak about the sense of a statement – of its thought – we are speaking about a verificational rule of p, for example, whose application we are able to thought, even if only partially. But when we are speaking about the whole procedure of verification, we are speaking about the process of achieving or not achieving the correspondence relation, namely, the match or mismatch between the numerically different verificational rules or f-thoughts. In the foregoing case, for example, what we have is a match of contents between the conceived verificational rule ?p and the effectively applied verificational rule !q. And it is effectively applied because it is the result of the effective application of the conjunction of the different verificational rules !r & !s & !t & !u, each of them having been the submitted to a similar process.

   To make the point clearer, I can give a simpler example. I get my car to go to the university in order to give a class. As I enter in the free-way I see that the amount of cars is unusually small. I begin to ask if it is a holyday. This is ?p. I do not thing about the many ways I know to verify this hypothesis. But I know its implications. One of them is that I will not have any class today; another is that I am losing my time. These inferences are constitutive of the meaning of the hypothesis ?p. Since I am without mobile phone, some minutes later I am in the university only to see that it is closed. I ask the policeman, who answers that today is a state holyday. My awareness that in fact it is holyday is the result of the effective application of the rule by a cumulative satisfaction of criteria, the last of them letting any doubt. This is !q. Since p is congruent with q, p is true. But first, both express the same verificational rule, though differently (and partially) considered and applied, both express the same meaning (even if differently and partially accessed). Second, I can consider that I verify that today is holyday considering the whole process described in the form ‘?p, !q, p = q/├p’, and can call it a verification. But in this sense verification cannot be identified with the meaning of a proposition.  
   Finally, returning to Husserl’s theory of truth, one need to note that it has, according to its interpreters, at least two main drawbacks. The first and more serious is that working only with intentional material Husserl is unable to explain the access to the object ‘in person’, to the object in itself, since this would demand him to go beyond the phenomenon.[14]
   Our understanding of correspondence allows us to escape from these limitations. In our words the thought ?p, which is for us a non-applied thought, but in some measure a rule of verification in its conceived application, is the same as what Husserl calls a meaning giving intention. A thought-content like !o, which is for us another rule of verification that can be similar to ?p, is the applied rule of verification, which is what Husserl calls the meaning fulfilling intentional act. And the awareness of the identity (or the congruence) ‘p = o’, which brings us to the conclusion ├p (that p is true) is the same as Husserl’s conclusion that the objects of the two acts are the same.
   However, we do not need to follow Husserl here. As you remember, according to our analysis the existence is the effective applicability of a conceptual rule, the truth-maker, the giving fact, has to do with the effective applicability of a verificational rule. This rule demands for its application the satisfaction of criterial configurations. These criterial configuration, on the other hand, when perceptual, can be interpreted not only as a configurations of sense-data, but also as real parts of empirical things (as configurations of tropes), as far as they satisfy the (inherent) criteria of external reality (the maximal intensity of sensation, the independence of will, the possibility of intersubjective access…). These configurations are at least parts of the ‘object in person’, but although depending from sensory contents, they can be seen as externally real in complete independence of them. And they exist in the independence of them because the existence of the fact is the effective applicability of the verificational rule, of the thought corresponding to it.
   The second objection against Husserl’s view is that the object is never given to us in its entirety. Since what we experience are always of parts of the object, it cannot be really given to us ‘in person’. In the end Husserl saw this problem and suggested that the object should be seen as an inferred X.
   Also under the view we have proposed it is true that neither the object nor the fact is perceptually given to us in their entirety, with the consequence that we cannot be absolutely sure that what is being given to our experience is the real object or fact. However, we can infer that the object is given with enough certainty to warrant the evidence of !o and, consequently, the truth of !p, at least under the circumstances of an adequate linguistic practice. We can infer that we have seen a dolphin and not only the back of a dolphin moving on the water, and we can postulate what is given as an evidence insofar as we can assume the circumstances of the language game we are playing as undefeated.




NOTES

[1] We remember here Alfred Tarski’s disquotational formula, according to which ‘“p” is true in L ≡ p’. Tarki’s formula hasn’t overcome the philosophical (epistemological and ontological) problems concerning correspondence, since it would say that in the case in which Fa, F is satisfied by the object referred by a, but does why it is satisfied by a certain object and not by any other, since it does not say under what conditions the referred object satisfies F. However, I think that Tarkir’s approach has properly emphasized the metalinguistic character of the truth-assignments. (See Alfred Tarsky: ‘The Semantic Conception of Truth’, Philosophy and Phenomenological Research, 4, 1944, 341-375).
[2] Edmund Husserl: Logische Untersuchungen II (Tübingen: Max Niemayer Verlag, 1980), chapter VI. See also Robert Sokolowski: Russellian Meditations (Evanston: Northwestern Univerisity Press, 1074), chap. 9.
[3]  Moritz Schlick, ‘Wahrheit als Korrespondenz nach der modernen Logik’ (1910), in Philosophische Logik (Frankfurt: Suhrkamp 1996).
[4] I take this distinction from the phenomenology: it is the distinction between ‘truth of correctness’ (Wahrheit als Richtigkeit) and ‘truth of disclosure’ (Wahrheit als Entdeckheit). See Robert Sokolowski, Introduction to Phenomenology (Cambridge: Cambridge University Press, 2000), p. 158.

[5] To demonstrate the truth of logical principles, Schlick suggested the reverse procedure: to obtain the required intuitive assessment of its application, the principle needs to be compared with a concrete example. M. Schlick: ‘Das Wesen der Wahrheit nach der modernen Logik‘, p. 82.
[6] “Truth”, in A. J. Ayer: The Concept of Person and Other Essays (London: Macmillan Press, 1963) p. 186.
[7] Bertrand Russell has a similar proposal in the paper ‘The Relation of Sense-data to Physics’, in his Mysticism and Logic (London: Penguin Books, 1953).
[8] G. E. Moore, ‘The Meaning of Real’, in his Some Main Problems of Philosophy (London: George Allen & Unwin, 1953).
[9]  I answer the sceptical problem distinguishing between inherent and adherent senses of reality in the chapter 6 of my book Lines of Thought: Rethinking Philosophical Assumptions (Cambridge Scholars Publishing, 2014).
[10] Wilfrid Sellars: Empiricism and the Philosophy of Mind, Minnesota Studies in the Philosophy of Science, vol. 1. (eds.) H. Feigel, M. Scriven (Minneapolis MN: University of Minnesota Press, 1956), pp. 253-329, sec. 3, 12, 18, 19, 30, 32. In my understanding, however, though the component unities of a sense-data cannot be conceptually grasped in themselves and by themselves, they can be conceptually grasped as the elements integrated with the whole unity of what is being perceived.
[11] Edmund Husserl: Logische Untersuchungen, VI, sec. 38.
[12] Edmund Husserl: Logische Untersuchungen, sec. 37.
[13]  According to Husserl truth is the identity between what is intended (gemeint) and what is givent, while knowledge is the identity between what is meant (gemeint) and what is given. Since I do not see the difference, I will restrain myself to the concept of truth. I will also let out Husserl’s speculation on the different senses of truth
[14] As Günter Patzig has noted, here ‘the daring bridge called evidence intended to connect the judgment with the fact had the drawback, rather unfortunate in a bridge, that it ended on the same side of the river from which it began’, in ‘Husserl on Truth and Evidence’, in J. N. Mohanty (ed.): Readings on E. Husserl’s Logical Investigations (De Hague: Nijhoff, 1977), p. 194.