THIS IS A VERY ROUGH DRAFT OF A WORK IN PROCESS
BASIC EPISTEMOLOGY
Preface
I.
Origins of
Knowledge
II.
Definition of
Knowledge
III.
The nature of
justification
IV.
Justification and
Truth
V.
Limits of
Knowledge
Una vez que tenemos
un sistema, podemos passar a demontarlo. Primero el árbor, déspués el sérrin. Y
uma vez alcançada la etapa del sérrin, hiemos de passar a la siguiente, a saber
la construcción de nuevos sistemas. Hay tres razones para ello; porque el universo
es, él mismo, sistémico. Porque ninguna idea puede tornar-se completamente
clara, a menos que se halle incluida em algún sistema y porque la filosofia del
sérrin es bastante aburrida.
[Once we have a
system, we can set to dismount it. First the tree, then the sawdust. Once we
reach the sawdust, we can turn to the follow, namely, the building of new
systems. There are three reasons for this: first the universe is, in itself,
systemic, because no idea can become sufficiently clear, unless it is included
in some system, and because the philosophy of the sawdust is quite tedious.]
Mario Bunge
PREFACE
(To be written…)
I
SOURCES OF KNOWLEDGE
Darwin’s idea is like a universal acid: it eats through just about
every traditional concept, and leaves in its wake a revolutionized world-view,
with most of the old landmarks still recognizable, but transformed in
fundamental ways.
Daniel Dennett
Epistemology is usually
defined as the investigation of the sources,
nature and limits of knowledge, that is, from where knowledge comes, how it
is constituted, and how far it is able to go… I begin in this chapter by considering
from where it comes from.
Some sources of knowledge are always
mentioned in the literature: experience,
priori access, memory, and testimony. The
first two sources are primary, while the second two are secondary, since they
are tributaries to the first ones. If I have the memory of having let my car in
the parking lot, it is because I had the experience of having let it there. If
I remember the modus ponens, it is because I have learned this logic rule
as part of my supposed a priori knowledge. False memories are not rare; they
are not real memories, because they do not correspond to their sources.
However, memory is mandatory: a person who loses her memory will have her
capacity for knowing practically eliminated. Testimony is also an important
secondary source of knowledge. We often gain reliable knowledge by means of
information given by other people. Moreover, testimony has been amplified today
by a plethora of new methods of obtaining information given by others, like
radio, television, newspapers, books, and all the information at disposal at
the internet. Testimony is but a secondary source, since ultimately all this
information will be based on the primary sources of sensory experience,
intuition and reason. No
doubt, experience and a priori access are the chief candidates to the role of
primary sources of knowledge.
The main divide between rationalist and
empiricist philosophers in the philosophical tradition concerns the extension
of the a priori knowledge. Rationalists (Plato, Descartes, Spinoza, Leibniz,
Hegel…) always tended to emphasize the importance and extension of the a priori
knowledge, if possible eschewing experiential knowledge. Empiricists, on the
other hand, tended to emphasize the role of experience, reducing the a priori
knowledge to non-substantive propositions (Locke, Hume…), if not trying to
eschew this form of knowledge completely or almost completely (Quine, Stuart
Mill…). This distinction is inevitably vague, since there is a range of levels
and kinds of rationalism and empiricism.
Our next question is what is,
more precisely, experience, and what is, more precisely, a priori access.
The first question seems to be
easier to answer. It gives us the so called a posteriori or empirical
knowledge. When we speak of experience, we usually refer to the perceptual
experience given by the five senses of the world around us. Example is a
statement like “This computer is on”. But we can also refer to the
reflexive or introspective knowledge we have of our mental states like sensations,
feelings and thoughts. Statements like “I feel pain” and “I think that
Schliemann discovered Troy”, are of this kind. Even occurrences of thought are
experiential, since like the other cases, they are contingent and occur in time
and space. And as Laurence BonJour noted, even the cartesian cogito é
experiential. Moreover,
much of our knowledge is indirectly obtained from experience, as our knowledge
that the tyranossaurus was a carnivorous reptilian or that gravitational waves
can change the spacial dimensions of physical objects.
The second question is
philosophically more difficult. It concerns the nature of the a priori knowledge.
Kant seems to be the first person to have suggested the term ‘a priori’ applied
to judgements. He has defined the a priori judgement negatively, as a true
knowledge that does not need to be justified by experience, even if it
presupposes the experiential learning of its constitutive concepts. In
order to make it clear, I give the following list of candidates of a priori
statements:
1.
Bachelors are not married. Triangles have three sides.
If Mary is the mother of John, then John is the son of Mary. a = a.
2.
1 + 1 = 2. A
cube has 8 edges. The sum of the angles of a triangle is 1800.
3.
P = P. ~(P & ~P). P v ~P. P & (P → Q) → Q. (P
& Q) → P. (~P v Q) → Q. A > B, B > C, hence A > C.
4.
We should not cause suffering to innocent people. Social
justice is equity. Moral action must search the highest happiness to the
majority.
5.
A colour has extension. The same surface cannot be
read all over and blue all over. Any event must have a cause. The universe is
uniform.
Consider (1): they are cases of a priori knowledge typically called
analytic. We can define an analytic statement as the statement that is true in
virtue of the arrangements of the meanings of its semantic components.
A property of these statements is that their negation produces a contradiction
or an incoherence. Triangles do not have three sides contradicts the definition
of triangle as a closed plane geometric figure with three internal angles and
three sides. These kind of statements are easily transformed in logical
tautologies by replacement of synonymic expressions (pace Quine) like
“[Non-married adult males] are non-married” in the place of “Bachelors are
non-married”. (Most empiricist philosophers try to reduce the knowledge a
priori to this more innocuous case.) The examples given in (2) and (3) are
respectively from mathematics and logics. Many believe that at least the
principles of these formal sciences are intuitively given a priori. (4)
exemplifies some ethical principles. (5) exemplifies some candidates to what we
could call synthetic a priori judgements, which would be statements a priori
but able to tell something about the world.
Their identifying criterion is that, differently from analytic statements, they
can be negated without contradiction.
Difficulties in defining a priori truths
Kant has seen necessity and strict universality as the marks of a priori
truth. Contemporary epistemologists have weakened this exigence. For many, the
a priori knowledge can be fallible.
This failure can occur, not only because it can be mistakenly accessed, but
also because it can be defeated, either by the emergence of other a priori
knowledge or by the cumulation of recalcitrant experience.
We saw Kants negative
definition of a priori knowledge. Necessity and strict generality would be
positive traits, but we have abandoned them. In the case of experience, we can
give a positive characterization by saying that the access is experiential and
speak of external or internal spatiotemporal entities that cause it. But there
is no analog concerning the a priori. Instead of experience we can recur to
terms like ‘aprehension’, ‘insight’, ‘intuition and reason’. Terminologically, it
is helpful to distinguish two kinds of a priori access: intuition, when
it seems to be directly given to us, and reason, when it demands a
reasoning process beginning with intuitions. Consider, for instance, the two
following examples of a priori knowledge: “1 + 1 = 2”, and “29,324 + 18,916 = 48,240”.
The first is intuitively reached, since we do not need to use reasoning in
order to aprehend its truth. The second one, however, demands reasoning in
order to be seen as true, at least in the case of normal human beings. An
important point to be noted is that the distinction between both cases is
variable according to the epistemic agent and to a certain extent to her
training. God would have only intuitive knowledge of the a priori, since he
would not need to use reasoning to know the results of what we inferentially
know. It is useful to preserve this understanding of the word ‘intuition’.
Traditional rationalist philosophers tried
to furnish a corresponding simile to the perceptual experience appealing to
mystic-religiose explanations. Thus, Plato suggested that we acquire knowledge of ideas through reminiscence.
Hence, if I see a triangular object, it contains an imperfect copy of the idea
of tringle; this makes me remember the abstract idea of the tringle, with which
my soul has been in contact when it was hovering in the world of ideas, before
its incorporation in a human body (notice that interpreters doubt to what
extent Plato’s resource to this wat not an elucidative resource). Hence, knowledge
results from recollection (anamnesis).
Anticipating the opposition between rationalism and empiricism, he classified
the former as “friends of ideas” and the latter as “earth-born giants”, Augustin defended the doctrine of divine illumination. We learn the
truths of mathematics, of aesthetics and morality because God illuminate us,
making us to remember them when we look at the interior of our souls. For
Descartes things could not be much different. We have the idea of God as the
being that has all the perfections. As we are imperfect, this idea cannot be
originated from ourselves. Hence, God exists, and he placed since the beginning
his idea in us as an innate idea. As an infinitely good being, he allows that
we have access to a priori truths that possess the marks of clarity and
distinction that we find in the (a priori) ideas of mathematics. Although very
few today accept this kind of explanation, it is important to see that it
always appeals to innatism. Leibniz was well-known by regarding innate ideas as
dispositional. According to him, experience is like a sculptor chiselling away
at a block of marble to expose the sculpture already present inside it, namely,
the innate ideas
1. Different methodological sources
It is worth to
notice that rationalist philosophers have historically assigned great value to formal
sciences. They tried to import the kind of deductive reasoning used in
mathematics into philosophy itself, insofar as they could infer knowledge
deductively from adequate intuitions. Plato required knowledge of geometry as a
condition for admission to his academy. Descartes was a great mathematician who
invented analytic geometry. Leibniz invented the infinitesimal calculus.
Spinoza was not a mathematician, but he tried to give an axiomatic structure to
his Ethica.
Empiricist philosophers didn’t have a great
difficulty with the epistemological access to the empirical world, since it
seems to be natural. Their view was that experience is the source of all (or
almost all) our substantive knowledge. Real knowledge should be a posteriori. Above the mathematics,
they tended to praise the inductive reasoning of empirical sciences, as Locke,
who lauded the incomparable
scientific work of Newton at the beginning of his Essay. Locke can be seen as a kind of prototype of an empiricist
philosopher. His metaphor of the new born child’s mind was a blank sheet (a tabula rasa) waiting to be filled by
experience. This metaphor illustrates as much the force as also the weakness of
the empiricist view. The force lies in its openness: nothing is warranted
beforehand. The weakness lies in the fact that it gives us no idea of how it is
possible that a whole edifice of knowledge can be constructed from nothing beyond
random experience. (As Karl Popper once wrote, if someone asks us simply “to
observe…”, this question will make no sense until the person tells us what to observe, giving us in this way
some direction.) Empiricism also does not explain how these resulting contents
can contain enough similar grounds to allow interpersonal agreement. As a
defender of rationalism, Popper ridiculed empiricism, suggesting that it is a
theory of the mental bucket. Empiricists, he wrote, believe the mind of a new born
is like an empty bucket. In time this bucket is slowly filled with material
coming from our senses, this material accumulates and becomes digested as
knowledge, though no one would be able to tell how.
Against this naïve theory of the empty bucket, Popper proposed his own view:
the spotlight theory of knowledge. We are predisposed to inquire about the
world in determinate ways, and by allowing our ideas to be refuted by
experience, we make ourselves able to create new and better ways to understand
it.
Against rationalism, it makes sense to point
out the religious or mystical ingredient that is often – though not necessarily
– involved. Nietzsche was the philosopher who identified in Socrates-Plato what
he called the negation of life, an attempt to escape from the hard vicissitudes
of human existence into a transcendent world outside space and time.
Philosophers, as persons used to the life of thought much more than to the life
of action, are particularly prone to this form of escapism.
Nonetheless, this susceptibility alone is
certainly not what sustains rationalism. For some problems it was rather the
only explanatory way available before the Darwinian revolution. The mystical
ingredient can be false and rationalism true, and many contemporary friends of rationalism
(Carl Jung, Karl Popper, Jean Piaget and Noam Chomsky, to name just a few) have
nothing mystical in their worldviews. In what follows, I intend to show that we
can capture the important element of truth in the rationalist persuasion
without having to necessarily embrace any form of mysticism.
2. Evolutionary induction
It is not
difficult to agree with the empiricist when he says that much of our knowledge
is a posteriori. But the thesis that all our knowledge is a posteriori has
always been seriously questioned, at least for the reason that the mind must in
some way construct and organize the empirical experience in order to achieve
knowledge. However, one cannot today explain the origin of the a priori
intuition appealing to the world of ideas, where the soul lived before being
incarnated, like Plato, or to God’s will to insert innate concepts in our minds
in the form of clear and distinct ideas, like Descartes. It is at this point
that the theory of evolution comes into play.
Daniel Dennett has often noticed
that the pre-Darwinian explanations of the origin of species were of the kind
“Top-Down”. For
instance: God created the man and all other species once and for all. On the
other hand, post-Darwinian explanations of the origin of species are of the
kind “Bottom-up”. According to them, the human being is the result of more than
a million years of a blind process of trial and error called natural selection.
Now, the same idea can be applied to our propensions to cognitively build a
priori knowledge, or, to be more careful, a priori beliefs. A priori truths can
be originated from our innate capacities and dispositions.
In our times the most plausible way to
defend rationalism, even if in a modified form, consists in the appeal to
natural evolution. Carl Jung posed the idea of an inherited collective
unconscious, built by archetypical structures that work as innate trigger
mechanisms, even if later speculatively exaggerating the role of these
structures. Popper
has called our attention to the philosophical relevance of filial imprinting in
animals.
As Konrad Lorenz observed, in the critical period between 13 to 16 hours after
hatching greylag geese develop the disposition to follow the first object that
moves before them, which normally is their own mother. However, it can be any
unexpected moving object, such as Lorenz’s moving boots. After imprinting, they
followed Lorenz wherever he went. Popper noticed that we also have innate
dispositions to form some primitive “theories” about the world. But unlike
Lorenz’s geese, we are able to correct
them. This is a kind of flexibility that has proved very helpful to our
survival. In fact, something near to imprinting in human beings might be
reverse sexual imprinting, which would be the tendency of children born and
raised together not to feel sexual attraction to one another.
In human beings there are, however, many other manifest inborn dispositional
traits, like the disposition of small children to look to the eyes of their
mothers when called, which makes possible the also innately determined capacity
of reading facial expressions, which plays a crucial role in the socialization
process.
Another interesting case is that of a rare deficiency called prosopagnosia
(face blindness). People with severe prosopagnosia are unable to identify the
faces of other people, including their own image in a mirror. This means that
the ability to construct images of many different faces and retain them in
memory is innate. More theoretically, Jean Piaget’s well-known
four stages of children’s cognitive development must to a great extent be
genetically programmed.
Furthermore, we need to explain how children are able to learn their mother
tongue rapidly from the ages 2 to 5 years. It seems necessary to posit some
kind of what Noam Chomsky called a language acquisition device in order
to explain this ability,
particularly when we consider that those children later lose this ability.
Doubtless, we have a multiplicity of complex
innate dispositions and capacities that lead us to react in this or that way,
and may cause us to develop cognitive responses that might correspond to what
rationalist philosophers understood as innate ideas and thoughts, insofar as we
are adequately stimulated. Since the first goal of natural selection is not
truth, but mere survival, we cannot expect that all these selected dispositions
and capacities are those that make us to acquire prima facie true
beliefs. But some of them must do precisely this, since knowing the truth is a
key to survival. As Michael Devitt noted,
if a belief is beneficial to the survival, it is to expect that the process of
natural selection makes with the time innate a disposition to entertain it.
This does not mean that the belief must be true. Devitt’s example is that of
religion; it may be that we have a predisposition to adopt a religious belief, which
can help us to collectively survive, without this religious belief being truth.
Another example could be the defence mechanisms considered by the
psychoanalysis, as the negation, the projection, the repression, the
rationalization and the sublimation. These mechanisms might have nothing to do
with the search of truth, but they are necessary to protect the psychological
structure of a person. However, as Devitt also noted, it may be that the
disposition to form a belief is beneficial precisely because it is true, being
by this reason selected. This is an important point only that Devitt
consider this argument as complementary to his view that there is no a priori
belief.
I take a different stand; I think this argument shows the empirical origin of
our priori beliefs.
If we apply this kind of reasoning to the
concepts and thoughts prized by rationalist philosophers like Plato, Descartes
or Kant, we would have an evolutionary explanation for the role they give to a
priori knowledge. This knowledge would not be the result of some intellectual
intuition of essences, or of the soul’s grasping of eternal ideas in the
Platonic realm, or something innately given to us by the Cartesian God, but
simply the result of a displaced form of induction that I wish to call evolutionary induction.
This idea of evolutionary induction must be explained
and justified. In order to do this, I begin by considering a trivial case of inductive
numerical generalization. We can formulate this kind of induction using the
symbols F and G in the place of physical and cognitive events respectively, and
↑P in the place of ‘very probably’, numerical generalizations can be roughly symbolized
as:
Fx → Gx
Fx → Gx
(…)
↑P (x) (Fx → Gx)
For instance: if
a first fire makes warms, a second fire makes warms, and so on… one can
conclude that (very probably) all fire warms.
It is true that our knowledge of the
empirical world is often and more primarily reached by cognitive numerical
induction, namely, from the experience of frequent association of different
facts in time and space, like fire with light or warmth. In order to illustrate
this, suppose an imaginary case of a cognitive being not endowed with any
geometric intuition, using rules to discover what kind of line covers the
shortest distance between two points. This inductive reasoning could receive
the following canonical form:
Schema A
Numerical inductive generalization:
- [Fx] The line covering
the shortest distance between these two points, [Gx] then it is measured
as a straight line.
- [Fx] The line covering
the shortest distance between these other two points [Gx], then
it is measured again a straight line.
(…)___________________________________________________
- Hence, probably: [Fxs]
All the lines covering the shortest distance between two points are [Gxs]
to be measured as straight lines. In symbols: ↑P (x) (Fx → Gx)
Now, one can
argue that our innate dispositions, prompting us to react to adequate stimuli
building some kind of intuition or reason (generating a priori concepts,
judgments, and reasonings) had a similar inductive source, not in epistemic
subjects, but in the evolution of the species. As we have seen, at least in
some cases, natural selection chose the members of a population that have
phenotypical traces more adequate for survival in their surroundings, at least
until the age of reproductive maturity, simply because they react by having
thoughts that are true in the sense of corresponding with reality. However, it
seems clear to me that in this case we also have an inductive process. It is
inductive at the evolutionary level. We can suggest that this occurs in animals
and particularly in human beings, even if in the latter case with results that
can be further treated in much more flexible ways, since handled by the
intervention of many contextually and culturally developed variables, so that
instead of speaking of stimuli we should here rather speak of adequate circumstances,
cultural contexts, life forms.
I think I can give a convincing example of
evolutionary induction that goes beyond a mere analogy. It concerns the
well-known fate of applied Euclidian geometry. Kant considered its principles
to be examples of synthetic a priori judgments, ways the mind is able to
legislate on the phenomenal world of experience. For him, statements like “a
straight line is the shortest distance between two points”, “through a point
outside a straight line only one parallel can be drawn”, or “the sum of the
internal angles of a triangle is 1800.”
This certainty disappeared soon after Kant’s
death, with the discovery of non-Euclidean elliptical and hyperbolic
geometries. This has shown that there were at least logically possible worlds
where the principles of Euclidean geometry do not apply. Worst of all, in 1915
the general theory of relativity showed that real physical space does not
follow a Euclidian geometry, but an elliptical Riemannian geometry which
changes depending on the curvature of space-time under the influence of
gravitational fields.
This curvature, however, is too small to be perceived by us in our
surroundings. It can be measured only as the result of gravitational fields in
cosmological dimensions. Thus, if you draw a triangle between the Earth, Mars and
Jupiter, you will see that the sum of its internal angles is greater than 1800.
The conclusion is that natural evolution has
endowed us with the intuitions of Euclidean geometry because it is not only
simpler but also precise enough to allow us to deal successfully with our
surroundings, and this is what mattered for our ancestors’ survival. Hence, it
is easy to understand why we were selected by evolution to understand and see
Euclidian geometry in a more direct and natural way as part of our genetic
endowment. We have the a priori intuition that we can draw only one straight
line between any two points. We see by some “natural light of reason” that we
can draw only one parallel line through a point outside a straight line and
that the sum of the internal angles of a triangle must always be 1800.
I understand these proclivities as legitimate results of evolutionary induction
in the following way. Across many generations, natural selection has eliminated
those members of our species without any ability to think using Euclidean
geometry, and preserved those members more or less endowed with the capacity
for thinking with this geometry. Notwithstanding its own limitations, Euclidian
geometry had the great advantage of furnishing us a sufficiently reliable point
of departure. (Bertrand Russell wrote in his Autobiography that as he was a
child, he deduced most of Euclidian theorems without having read the Elements;
he had a better innate endowment to understanding Euclidian geometry than most
of us.)
At first view, ‘evolutionary induction’
might seem a strange expression for a strange form of induction. However, this
impression disappears once we see that the inductive result does not need to be
restricted to the psychological experience of an existing epistemic subject, or
even of any collaborative community of epistemic subjects. To restrict
induction to a psycho-social phenomenon is a chauvinist prejudice. Inductions
are logical inferences that by chance instantiate cognitively in human
epistemic agents. But this is a contingent fact. Induction can be instantiated
in an adequately programmed computer. In a similar way, induction can be
instantiated in the process of natural selection in order to produce shared
innate propensions to reach a priori beliefs. We only displace the experience
of the individuals to the “experience” of a species. The above described result
of evolutionary induction isn’t structurally different from our normal
processes of induction by enumeration, except for the fact that it is coupled
with a process of natural selection in which the social disposition for the
inductive conclusion, which appears to us in the form of intuition or reason,
can take many thousands of years to fully develop. Here is a schema regarding
the shortest distance between two points provided in the long run by our
evolutionary induction:
Schema B
Evolutionary inductive generalization:
A member of the species is able to
survive [Fx] by seeing straight lines as [Gx] the shortest
distance between two points.
Another member of the species is
able to survive by [Fx] seeing straight lines as [Gx] the
shortest distances between two points.
(…)___________________________________________________
Hence, very probably: The selected
members of the species have the intuition that always that [Fx’s]
straight lines are seeing, they are [Gx’s] the shortest distances
between two points. In symbols: ↑P (x) (Fx → Gx)
The structure of
schema B is similar to the structure of schema A, not as an individual
induction but as a fragment of our own species-induction. It seems that we have
good reasons to think that cognitive dispositions and capacities that at first
view seem to be the result of the natural light of reason are in fact an
inductively grounded end-product of natural selection. Evolutionary theory has
made plausible the idea that rationalism can be understood as having after all
an empiricist inductive basis in the general process of evolution.
Finally, the idea of
evolutionary induction – a species-induction – is supported by the view
according to which species are spatiotemporally enduring individuals.
If it were possible to bring to the earth an animal from another galaxy that
were identical to our tigers, having the same genetic layout and being able to
inter-crossing with our tigers, we would resist to classify this animal as a
tiger. After all, tigers are animals that have developed in Asia. Because of this,
we should treat a species as an individual that develops itself during the
time, in a similar way as we can treat a colony of ants as an individual. This
is an additional reason to think that species are able to select their members
in an inductive form.
The final conclusion is that
the theory of evolution suggests that the origin of our so-called a priori
intuitions and reasonings is not a mystical one. This origin lies in inherited
proclivities. It is these proclivities, along with adequate experiential
stimuli, which lead us to have intuitions and reasonings that we see as a
priori justified. A priori justification is the justification settled by the
experience of our species.
3. Examining supposed counterexamples
One could object
that this conclusion is too hasty, since most intuitions and reasonings that
are important for the rationalist philosopher seem to have little, perhaps
nothing at all to do with most of the dispositions and capacities initially
considered. They are moral views, logical principles, arithmetical judgements
and, mainly, metaphysical principles like the view according to which all
events must have causes, or the libertarianist view of free will as
transcending causal constraints. At first view, such abstract ideas do not seem
to have as their source innate dispositions resulting from natural evolution.
Moreover, we also have seemingly unavoidable metaphysical concepts, like those
of substance, property, number and existence, which do not seem to be
empirically explainable.
One can answer this objection by saying that
many of these intuitions have indeed an evolutionary source, some of them being
of such a general kind that they must belong to any evolutionary endowment, but
this does not prevent them from being illusory. In what follows, I will
consider them separately.
1.
Analytical statements. There is the more trivial
case of conventional definitions like “A square is a special kind of rectangle”
or “Bachelors are not married”, and even stipulative trivialities like “a = a”. They are analytical
because true in virtue of meaning. The kind of a priori called analytical in
the Fregean sense, that is, able to be transformed into logical tautologies by
substitution of terms. Thus, since “A square (Df.) = a rectangle with equal sides”, we can derive the tautology
“A rectangle with equal sides is a rectangle”, and since “A bachelor (Df) = a non-married adult male”, we can
derive the tautology “A non-married adult male is non-married”. Something
important to see about analytic statements is that most of them are not
arbitrarily built. The above convention exists and is useful because there is a
difference in the world between married and non-married adult males. In
themselves, analytic statements are frozen as eternal truths; what might occur
is that their application can be eroded by changes in the world and
consequently in our conceptual system. In a society where there is no place for
marriage there will be no usefulness for the concept of bachelor. However, their
truth-value should not be confused with their usefulness (pace Quine).
2.
Moral proclivities. Moral dispositions clearly have
evolutionary origin. Men are social animals. Consider the moral rule: “Do not
harm innocent people”. Even if this can be object of critical thinking, it
serves as a rule of thumb. We are endowed with moral dispositions, and if we do
not follow them and we do not lack these dispositions (as in the case of
psychopaths), we are damned to feel bad conscience. Moral principles like “We
should act in order to increase the general well-being” or “We should not do to
others what one would not like to get done to ourselves” are selected because
they further the collaboration in a community and human society does not thrive
without this collaborative element.
It is interesting
to see that all these rules can be seen as a priori, though fallible. We can
always imagine situations in which their application can be wrong. But we feel
that there is something redeemable in them and that it is the task of moral
philosophy the attempt to refine them in order to make them undeniable.
Finally, one should pay attention to what is called epistemic
overdetermination: the possibility that our a priori justification is
reinforced or weakened by experience, through induction or refutation. In this
sense, epistemic overdetermination can be as old as
Plato’s teaching of geometry in the Phaedo, and as common as we might
suspect.
3.
Mathematical Truths. An interesting case is that of mathematical truths. I already considered
the case of geometry, showing that we were selected to have a priori intuitions
concerning Euclidean geometry, which seems more natural to us, though physics
has shown that it is not the real geometry of physical space in the universe.
We could here introduce the distinction between applied and abstract geometry.
As an applied geometrical statement, “The sum of the internal angles of a
triangle is 1800” is not a synthetic a priori truth, as Kant would
like us to believe, that is, an informative necessary truth concerning
objective physical space achieved independently of experience. It is synthetic
a posteriori and in addition false. On the other hand, this same statement can
be abstractly interpreted as an analytic or self-contained a priori truth,
insofar as we understand it as the result of the abstract construction derived
from the Euclidian system of geometry, leaving out of consideration its applicability
to the real world. This abstract geometry can also be considered necessary in
the sense that it cannot be false within the abstractly considered Euclidian
system.
Although some
would disagree, I do not see much difficulty in applying a similar kind of
reasoning to arithmetic. Consider the sentence “2 + 3 = 5”, which is usually
considered an a priori truth. We do not learn it directly. We must first have
the experience of counting objects like two pears and three apples in order to
get five fruits. Later, we learn to think that 2 + 3 = 5 is the abstraction of
any empirical counting. It is clear that the first capacity is innately
determined, allowing us to establish a later convention abstractly considering
2 + 3 = 5. In this way, 2 + 3 = 5 not only finds support in our everyday usage,
but if considered as an abstract convention (only conceived and never applied)
it can be seen as true by definition.
Now, suppose that we are in a possible world
called Omega, where when making any applied sum, a similar additional object
suddenly appears before us. For example, in the process of adding two pears and
three apples, what I see before me are six pieces of fruit: two pears and, say,
four apples, two of them exactly identical.
In this world, the applied sum 2 + 3 = 5 would be false. In fact, 2 + 3 = 6
would be the right result, the same occurring with the result of 7 + 5, which
would be 13... The difficulty we have to accept this conclusions rests in the
fact that we guess that this possible world would contradict all our physical
laws and it would be barely conceivable. Anyway, it remains at any rate a
logical possibility. In such a logically possible world, we would probably need
to produce an abstract conventional concept of sum that would need to be a different
one, supported by changes in applied arithmetic.
Like us, a
mathematician from the world Omega could make the mistake of supposing that
this form of applied addition is necessary and universal, so that it could be
extended to all possible worlds based on his mathematical intuition. However,
as we know from our own world, this would be faulty. And this suggests that
although he remains free to conclude, based on conventions, that 2 + 3 = 6 and
7 + 5 = 13, he cannot say that he can generalize this result as necessarily
applicable in all possible worlds, unless he interprets these sums
independently of their applications, as abstract arithmetic. In this case, he
could say that these results are necessary in the sense that they could not be
different in any possible world within his assumed abstract system of rules.
4.
Logical Principles. The cases of fundamental
logical principles seem different. Think about the principle of
non-contradiction: ~(p & ~p). Ontologically formulated, it means that it is
impossible that something is the case and isn’t the case at the same time and
from the same perspective. Logically formulated it says that a thought (a
Fregean proposition) cannot be true and false at the same time and under the
same interpretation. This principle can be seen as a priori and analytic (in
the sense that it cannot be denied without contradiction): it is too
fundamental to be falsified. Locke was of the opinion that we learn the principle of non-contradiction
from experience. For reasons already given, this cannot be true. In fact, we
must be evolutionarily so constituted that we cannot do anything, except to
follow the principle of non-contradiction inevitably inbuilt in our cognitive
mechanisms, since without this principle he would be unable to have any
cognitive experience. As Aristotle wrote, a person who denies this principle
would be mute like a tree. One cannot simultaneously affirm something and its
proper denial and claim to have said something. This applies to any cognitive
being. A cat cannot catch a mouse if it sees a mouse and a non-mouse at the
same time. A zebra that sees a lion and a non-lion at the same time will soon
have a difficult time. Hence, the necessity of the principle of
non-contradiction isn’t based on something like its intuition, but on its
universality. If we are not wild metaphysicians, we will feel our cognitive
inability to find an exception. Generally spoken, in cases as fundamental as
the principles of thought or the modus ponens, we cannot make a
distinction between applied and non-applied logics. And the reason is that
logic, in its fundamentals, is ubiquitous. This remembers us Wittgenstein’s
thesis according to which the possibility of representation is indebted to what
is ultimately common between representation and world, which for him was the
logical form or structure.
The principle of non-contradiction cannot be contradicted because as well our
thought as what it represents must be in accordance with it, the community
between both being justified by the natural selection. (Our capacity to apply
the principle needs to be distinguished from the kind of introspective act of
recognizing the principle in the thought. This act isn’t a priori. This act of
recognition was instantiated for the first time, it seems, by Aristotle in his Metaphysics.)
5.
Inductive Principles. Evolutionary induction has
also taught us inductive logic. It seems that we have intuitive belief in
principles like those saying that the future will preserve sufficient likeness
to its past to allow inductive inferences, because we are disposed to form
inductive habits, and this disposition cannot be other than a result of
evolutionary induction.
The same applies regarding something more sophisticated but equally important,
abduction, the inference of the best explanation. In order to make this
inference, we need a fact or set of facts leading us to infer the best
explanation for something. For instance, the best explanation for the different
phases of the moon, after considering different positions of the moon relative
to the earth and the sun – the sun always seen on the opposite side – was that
different angles of illumination through the sun were the cause. This kind of inference
must assume a multitude of previous numerical inductive inferences in order to
be possible. But the more sophisticated ability to make inferences about the
best explanation could also be the result of a selected disposition. Those
individuals able to associate several inductive evidences and see the common
explanation had better chances of survival and passing this ability on to their
offspring.
6.
Metaphysical Principles. Concerning legitimate
metaphysical concepts like those of properties, numbers, existence, external
reality, it is plausible that we also have inborn capacities to form them,
consciously or not. They are framework metaphysical concepts, and their
necessity is justified by their universality. We are not able to conceive any possible
world in which they would not be applicable. Consider, for instance, the
concept of external reality: we could say that the observance of natural laws
belongs to it in an aprioristic way.
More on the
opposite side, there are conventions that doubtless aim to reflect metaphysical
properties of empirical reality: “Red is a colour”, “Everything red is coloured”,
“Red is not green”, “The same surface cannot be red and green at the same
time”, “A physical body must have some extension”, “If A is taller than B, and
B is taller than C, then A is taller than C”... Although these statements all
seem to be true by convention, these conventions are more solidly anchored in
our grasp of the ways the world is constituted (the ways the world has selected
us to divide it up). Because of this, we feel the ease with which we can apply
the correspondence view of truth in order to warrant these statements: “Red is
a colour” corresponds to the fact that all reds are colours, “A physical body
must have some extension” corresponds to the fact that all physical bodies have
some extension.
There is also a
pragmatic point to be considered. These a priori statements, like the
linguistic systems to which they belong, must be useful insofar as they are
applicable to reality. The conceptual relations in these statements can be seen
as necessarily true, insofar as the corresponding systems apply to the world,
otherwise they will be unmasked as false and not necessarily true. But there is
no crucial difference between these cases and a statement like ‘Bachelors are
unmarried men”, since it could lose its point in a society in which bachelors
cannot be factually distinguished from married people. The only difference is
that statements like “Everything red is coloured” or “Things that are red are
not blue” require the acceptance of a more sophisticated system of rules that
in their cases define red patches as colours, and different colours as mutually
exclusive. A provisional conclusion is that we do not need to consider conceptual
truths as detached from reality only because of their usually conventional
character. Their conventions are not arbitrary; they can often be seen as
reflecting the metaphysical structure of reality as we are able to conceive.
There are also
metaphysical principles cherished by philosophers as “The future will be like
the past” (Hume) and “All events have a cause” (Kant). They would be easily
called synthetic a priori judgements. We can suspect overdetermination at work
in them: they can be learned through experience and at the same time be the
result of inherited proclivities. As stated above they are clearly wrong. Why
cannot an event occur without any cause? Why must the future be like the past?
Anyway, this does not mean that they cannot be refined in ways that make
difficult to deny them without incoherence. Since I will discuss the first
principle in the last chapter, I will try to refine the second one here. We can
first consider a minimalist form of it: “At least one event must be caused”.
Since our own experience is causal, this principle is verified by experience.
This is, obviously, a too weak principle to sustain causality. But we can
reformulate it as follows:
Causal
relations must be at least sufficiently common to justify our expectative that,
given one event, we might expect to find its causes.
Although we can
reject this version, we do it with a heavy hearth. We see that its rejection
makes natural laws impossible, making them impossible even concerning the
causal relation between objects and their perception. Since we cannot conceive
a world in which this relation would not be a causal one, it seems clear that
the reformulation (2) cannot be denied without incoherence being therefore an
analytic-conceptual truth.
7.
Illusory philosophical beliefs. Finally, there
is a lot of illusory philosophical knowledge. As hopelessly illusory, I would
choose the concept of substance as a kind of “I don’t know what” support for
the sensible qualities of material things that lie beyond any experience.
We can replace it by the material things themselves, maybe understood as
bundles of spatiotemporally located tropical properties, including what
physicists call ‘rest mass’.
Another hopeless case is the synthetic a priori principle that all events must
have causes.
We don’t need the appeal to Hume’s authority to say that this view has no
intuitive support. It is not difficult to imagine events without any cause and
the generalization to all events seems to be a philosophical fancy. (However,
if you say that at least some event must have a cause, I will tend to agree,
since it seems impossible to conceive the world without this assumption.)
Consider, finally, the “feeling of freedom”. Libertarians have appealed to this
feeling as evidence that we are able to transcend causal determinism in our
decisions: we feel that we could decide to do otherwise. However, plausible
compatibilist theories of free will, by explaining our freedom of decision as
constituted by the lack of restrictions on human decisions, justify this
feeling of freedom as caused by the intrinsic incapacity of our conscious minds
to become aware of all the causal
factors involved in the decision process.
Evolution shows
that cognitive beings that were selected as able to make the right kind of
association are able not only to protect their lives, but also to form ideas
that are often true. In the last case we have the process of evolutionary
induction. The evolutionarily selected cognitive beings have learned to
correlate their representations with the enduring associations of events under
adequate circumstances, reaching truths in the sense of correspondence, at
least to a relevant extent, even abstracting them in the form of analytical
truths. There is no absoluteness in these truths; but they are able to give us
points of departure. This is the real source of all our a priori intuitions and
reasoning. Plato’s anamnesis was a “Top-Down” foreshadowing of the end-product
of evolutionary induction, which is in fact a “Bottom-Up” process.
4. Conclusion
What should we
conclude from all these considerations? One could conclude with Devitt, that in
the end empiricism wins, since it seems that the ultimate source of our
knowledge is in both ways inductively originated from the interaction between
the senses and empirical reality. However, I am afraid that this conclusion
does not do justice to rationalism. Rationalism, like any philosophical
position, should be evaluated not by its errors, but by its insights. Plato was
in error by appealing to mythological explanations, but he was not to blame
regarding this, since they were the only clue that his time could bring. But
Plato was also prescient in believing that there is something innate steering
our experience. On the other hand, a rationalist system like that of Spinoza,
which is naturalist and treats the extended physical world as a different way
of presentation of the mental world, both of them belonging to the infinite attributes
of God or Nature or Substance, is compatible with evolutionary theory. A
proponent of evolutionary induction could reconstruct this system without
falling into contradiction.
Moreover, we can accept a considerable
amount of innately determined intuitive or rational a priori knowledge, insofar
as we admit, against old fashioned rationalists, that what we are assuming to
be knowledge is fallible. The belief in infallible a priori truths belonged to
a time when philosophers didn’t have any Darwinian option. Furthermore, there
is nothing in rationalism forcing us to reject induction. These would be naïve
and committed forms of rationalism. What really distinguishes rationalism in
its modern form seems to be its emphasis on the role of innate dispositions and
capacities in the construction of knowledge. And what distinguishes empiricism
is the emphasis on our minds’ ability to react before the accumulation of
empirical evidence, making use of the different forms of inductive reasoning in
order to develop or challenge our original dispositions and capacities.
Traditional empiricism, by rejecting innate knowledge also rejects Darwinian
answers, like the products of evolutionary induction, falling into the
exceeding poverty of mental buckets theory. More plausibly the two elements,
inborn propensities and inductive experiential procedures, must have a
complementary role to play in the development of human knowledge. In the same
way as psychology has overcome the opposition between inborn influences and
influences of the external world by admitting the unavoidable interaction
between the two, epistemology informed by evolutionary theory overcomes the
opposition between rationalism and empiricism. Insufficiently aware of the
evolutionary link, traditional rationalism and empiricism have respectively
over-emphasized either one or the other, according with the inclinations of
philosophers and philosophical movements. So considered this is a dichotomy
fated to disappear.
A curious point is that our innate
predispositions seem to be able to influence the chosen metaphilosophy. If you
are an empiricist or a rationalist is something that might be in part
determined by your gens and in part, of course, by the external determinants of
your intellectual growing.
