Ridling Zaine. Philosophy: Then and Now. A look back at 26 centuries of thought
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Ridling, Philosophy Then and Now: A Look Back at 26 Centuries of Thought
838
ethics, where normative questions about how one ought ideally to act are
asked.) This approach quickly takes one into the central domains of
epistemology. It raises such questions as: Is knowledge identical with justified
true belief? Is the relationship between evidence for a belief and the belief
itself a probability function? If not, what is it? What indeed is meant by
“justification” and what sorts of conditions have to be satisfied before one is
entitled to say that a belief or set of beliefs is justified? These two differing
aspects of epistemology are not inconsistent and indeed are often found
intertwined in the writings of contemporary philosophers.
Knowledge and Certainty
The relationship between knowledge and certainty is complex, and there
is considerable disagreement about the matter. Are these concepts the same? If
not, how do they differ? Is it possible for someone to know that p without
being certain that p? Is it possible for someone to be certain that p without
knowing that p? These are the central issues around which the debate
revolves. The various answers that have been proffered depend on how the
concepts of knowledge and certainty are analyzed. If one holds, for instance,
that knowing is not a psychological state but that certainty is, then one would
deny that the concepts are identical. But if one holds that knowing represents
the highest degree of assurance which humans can obtain with respect to the
truth of p, and that such a maximal degree of assurance is a psychological
state, one will interpret the concepts to be equivalent. There have been
proponents on both sides of this issue.
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Further complicating the discussion are subtle distinctions drawn by
20th-century philosophers. For instance, in “Certainty” (1941) G.E. Moore
claimed that there are four main types of idioms in which the word “certain” is
commonly used: “I feel certain that,” “I am certain that,” “I know for certain
that,” and finally “It is certain that.” He points out that “I feel certain that p”
may be true when p is not true but that there is at least one use of “I know for
certain that p” and “It is certain that p” which is such that neither of these
sentences can be true unless p is true. Moore argues that it would be self-
contradictory to say “I knew for certain that he would come but he didn’t,”
whereas it would not be self-contradictory to say “I felt certain he would come
but he didn’t.” In the former case, the fact that he did not come proves that
one did not know that he would come, but, in the latter, the fact that he did not
come does not prove that one did not feel certain he would. “I am certain that”
differs from “I know for certain that” in allowing the substitution of the word
“sure” for the word “certain.” One can say “I feel sure (rather than certain)”
without a change of meaning, whereas in “I know for certain” or “It is certain
that” this substitution is not possible. On the basis of these sorts of
considerations Moore contends that “a thing can’t be certain unless it is
known.” He states that this is what distinguishes the word “certain” from the
word “true.” A thing that nobody knows may well be true, but it cannot
possibly be certain. He thus infers that a necessary condition for the truth of
“It is certain that p” is that somebody should know that p is true. Moore is
therefore one of the philosophers who answers in the negative the question of
whether it is possible for p to be certain without being known.
Moore also argues that to say “Someone knows that p is true” cannot be
a sufficient condition for “It is certain that p.” If it were, it would follow that,
in any case in which at least someone did know that p was true, it would
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always be false for anyone to say “It is not certain that p”; but clearly this is
not so. If one person says that it is not certain that Smith is still alive, he is not
thereby committing himself to the statement that nobody knows that Smith is
still alive: the speaker’s statement is consistent with Smith’s still being alive,
and both he himself and other persons know this. Moore is thus among those
philosophers who would answer in the negative the question of whether the
concepts of knowledge and certainty are the same. Though it is widely
accepted that to affirm that somebody knows that p implies that somebody is
certain that p, the case of the slave boy in Plato’s Meno seems, at least at first
glance, to be a counterinstance. Meno may know, in a dispositional sense,
certain theorems of geometry without knowing that he knows, and, if he does
not know that he knows, then it would seem that he cannot be certain that he
does know. But it has also been argued that, once his disposition to know has
been actualized and his knowledge has become occurrent, then, insofar as he
does know in this occurrent sense, he is certain of what he knows.
The most radical position on these matters is to be found in
Wittgenstein’s On Certainty, published posthumously in 1969. Wittgenstein
holds that knowledge is radically different from certitude and that neither
concept entails the other. It is thus possible to be in a state of knowledge
without being certain and to be certain without having knowledge. As he
writes: “Instead of ‘I know’... couldn’t Moore have said: ‘It stands fast for me
that...’ ? and further: ‘It stands fast for me and many others....’” “Standing
fast” is one of the terms Wittgenstein uses for certitude and is to be
distinguished from knowing. For him certainty is to be identified with acting,
not with seeing propositions to be true, the kind of seeing that issues in
knowledge. As he says: “Giving grounds, justifying the evidence comes to an
end – but the end is not certain propositions striking us immediately as true –
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i.e., it is not a kind of seeing on our part; it is our acting which lies at the
bottom of the language game.”
Origins of Knowledge
Philosophers not only wish to know what knowledge is but also how it
originates. This motivation is based, at least in part, on the supposition that an
investigation into the provenance of knowledge can help cast light on its
nature. From the time of the Greeks to the present, therefore, one of the major
themes of epistemology has been a quest into the sources of knowledge.
Plato’s The Republic contains one of the earliest systematic arguments to
the effect that sense experience cannot be a source of knowledge. The
argument begins with the assertion that ordinary persons have a clear grasp of
certain concepts, that of equality, for instance. In other words, people know
what it means to say that A and B are equal, no matter what A and B are. But
where does such knowledge come from? One may wonder, for instance,
whether it is provided by vision and consider the claim that two pieces of
wood are of equal length. A close inspection of these pieces of wood,
however, shows them to differ slightly, and the more detailed the inspection,
via various degrees of magnification, the more disparity one notices. It
follows that visual experience cannot be the fount of the concept of equality.
Plato applies this result to the operations of all the five senses and concludes
that sense experience in general cannot be the origin of such knowledge. It
must therefore have another source, which he regards as prenatal (one such
account is found in the myth of Er in Book X).
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The mathematical example Plato selects to illustrate that the origin of
knowledge is not in sense experience is highly significant; indeed it is one of
the signs of his perspicacity that he should pick such an example. For, as the
subsequent history of philosophy reveals, the strongest case for the notion that
at least some knowledge does not derive from sense experience lies in
mathematics. Mathematical entities are abstractions – perfect triangles,
disembodied surfaces and edges, lines without thickness, and extensionless
points – and none of these exists in the physical world, i.e., the world
apprehended by the senses. It might be thought that, had Plato selected a
different example, say, the color red, his argument would have been less
convincing. But it is a further sign of his genius that he discusses colors as
well as mathematical notions and provides good reasons for holding that
seeing examples or specimens of red (or any other color) is not equivalent to
knowing what that color is. Such knowledge must therefore have a different
genesis than sense experience.
Innate versus Learned
The puzzle about origins of knowledge has led historically to two
different kinds of issues. One of these is the question of whether knowledge
(or at least certain kinds of knowledge) is innate, meaning that it is not
acquired or learned through experience but in some important sense is present
in the human psyche at birth. The matter is still a live issue today, not only in
philosophy but also in linguistics and psychology. The linguist Noam
Chomsky (b. 1928), for example, has asserted that the “projection
phenomenon” – the ability of children to construct sentences that they have
never heard before and that are grammatical – is proof of inherent conceptual
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structures, whereas the experimental psychologist B.F. Skinner (b. 1904) has
tried to show that all knowledge is the product of learning through
environmental conditioning by means of the processes of reinforcement and
reward.
In the extensive historical literature on this topic both the notion of
“innateness” and that of “learning” have been given various interpretations.
Sometimes, for instance, innateness carries only the sense of a disposition or
propensity, but in stronger versions of the thesis, such as Plato’s, it is affirmed
that humans possess actual pieces of prenatal knowledge. “Learning” also is
given a variety of meanings, ranging from trial-and-error methods to inexplicit
types of “absorption” of information. There are also a range of “compromise”
theories. These typically claim that humans have some knowledge that is
innate – the awareness of God, the principles of moral rightness and
wrongness, and certain mathematical theorems being favored examples –
whereas other kinds of knowledge – such as knowledge by acquaintance – are
gained through experience.
Rationalism versus Empiricism
The second issue that emerges from considerations of the origins of
knowledge focuses on the distinction between rationalism and empiricism.
Though closely related to the issue of innateness versus learning, the question
in this case concerns the nature of the source from which knowledge arises.
The history of discussion of the issue indicates that two main sources have
been identified and argued for: reason and experience.
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Rationalism is the thesis that the ultimate source of knowledge is to be
found in human reason. What reason is, in turn, is a difficult question. But,
generally speaking, it is assumed that reason is a feature of the human mind
that differs not just in degree but in kind from bodily sensations, feelings, and
certain psychological attitudes, such as disgust or enthusiasm. For some
writers, such as Plato, reason is a faculty, a special facility or structure of the
mind. Many later philosophers reject any sort of faculty psychology, and some
of them tend to interpret reason in dispositional or behavioral ways. But,
whatever the interpretation, a rationalist must hold that reason has a special
power for grasping reality. It is the exercise of reason that allows human
beings to understand the world they live in. Such a thesis is double-sided: it
holds, on the one hand, that reality is in principle knowable and, on the other
hand, that there are human, distinctively mental, powers capable of
apprehending it. One thus might define rationalism as the theory that there is
an isomorphism (a mirroring relationship) between reason and reality which
makes it possible for the former to apprehend the latter just as it is.
Rationalists affirm that, if such a correspondence were lacking, the effort of
human intelligence to understand the world would be impossible.
Empiricism is often defined as the doctrine that all knowledge comes
from experience. Almost no philosopher, however, has ever literally held that
all knowledge comes from experience. Locke, who is the empiricist par
excellence, thought there is some knowledge human beings have – which he
calls “trifling ideas” (or trivialities), such as a = a – that does not derive from
experience; but he regarded such knowledge as empty of content. Hume held
similar views.
Empiricism thus generally allows for a priori knowledge while
denigrating its significance, and accordingly it is more accurate to define it as
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the theory that all knowledge about matters of fact derives from experience.
When defined in this way empiricism does represent a significant contrast to
rationalism. Rationalists hold that human beings have knowledge about
matters of fact which is anterior to experience and yet which does tell them
something significant about the world and its various features. Empiricists
would deny that this is possible.
The meaning of the term experience is generally limited to the
impressions and sensations received by the senses. Thus, knowledge is the
information apprehended by the five sense modalities – hearing, seeing,
touching, tasting, and smelling. Such knowledge is always about matters of
fact, about what one can see, touch, hear, taste, or smell. For strict empiricists
this definition has the implication that the human mind is passive – a tabula
rasa, in Locke’s idiom; it is an organ that receives impressions and more or
less records them as they are. This conception of the mind has seemed
counterintuitive to many philosophers, especially those in the Kantian
tradition. But it also poses serious challenges for empiricists. For example, it
raises the question of how one can have knowledge of items, such as a dragon,
that cannot be found in experience.
In response, the classical empiricists such as Locke and Hume have tried
to show how the complex concept of a dragon can be reduced to simple
concepts (such as wings, the body of a snake, the head of a horse), all of
which derive from direct impressions of such items. On such a view the mind
is still considered to be primarily passive, but it is conceded that it has some
active functions, such as being able to combine simple impressions and ideas
into complex ideas.
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There are further difficulties: the empiricist must explain how abstract
ideas, such as the concept of a perfect triangle, can be reduced to elements
apprehended by the senses when no perfect triangles are actually found in
nature, and he must also give an account of how general notions are possible.
It is obvious that one does not experience “mankind,” but only particular
individuals, through the senses; yet such general notions are meaningful, and
propositions containing these concepts are known to be true. The same
difficulty applies to color concepts. Some empiricists have argued that one
arrives at the concept of red, for example, by abstracting from individual items
that are red. But the difficulty with this suggestion is that one would not know
what to count as an instance of red unless one already had such a concept in
mind; and, if that is so, it would seem that experience cannot be the source of
the concept. It is generally felt that, despite ingenious attempts by empiricists
to deal with such issues, their solutions have not been wholly successful.
Indeed, the history of epistemology has to a large extent been a dialectic
between rationalism and empiricism in an effort to meet sceptical challenges
that are designed to undermine both positions.
Scepticism
Many philosophers past and present and many nonphilosophers who are
studying philosophy for the first time have been struck by the seemingly
indecisive nature of philosophical argumentation. For every argument, there
seems to be a counterargument; and for every position, a counterposition. To a
considerable extent scepticism is born of such reflection. Some of the ancient
Sceptics contended, for example, that all arguments are equally bad and,
accordingly, that nothing can be proved. The American philosopher Benson
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Mates claims to be a modern representative of this tradition, except that he
believes all philosophical arguments to be equally good. But he insists that,
because they are, they invariably issue in conceptual deadlocks and resolve
nothing.
Ironically, scepticism is itself a type of philosophy, and the question has
been raised whether it manages to escape its own demurrers. Does it offer
arguments, and if so, are they decisive? The answers to these questions
depend on what is meant by scepticism. Historically, the term refers to a
complex set of practices taking many different forms – from stating explicit
theories to assuming negative attitudes without much propositional content.
Thus, it is difficult to define. But, however it is understood, scepticism
represents a set of challenges to the claim that human beings do possess or can
acquire knowledge.
In giving even this minimal characterization, it is important to
emphasize that both dogmatists and Sceptics accept a definition of knowledge
that implies two things: that, if a person, A, knows that p, then p is true and
that, if a person, A, knows that p, then A cannot be mistaken, meaning that it
is logically impossible that A could be wrong. If a person says that he knows
Smith will arrive at 9:00 AM, and Smith is not there at 9:00 AM, then that
person would have to withdraw the claim to know. He might say instead that
he thought he knew or that he felt sure. But he could not continue rationally to
insist that he knew if what he claimed to know turned out to be false.
It should also be stressed that, given this definition of knowledge, the
skeptic does not have to show that A is actually mistaken in claiming to know
that p. All he has to show is that it is possible that A might be mistaken.
Hence arises the skeptic’s practice of searching for a possible counterexample