Platonic realism
Platonic realism is a
metaphysical theory of
universals, maintaining that universals have a mode of being that is independent of the experiential mode of being. It is founded largely on the works of
Plato, partly inspired by the teachings of the
Pythagoreans, though it is but one aspect of both those philosophies. A due appreciation of this position depends on understanding that the relation
being independent of is not the same thing as the relation
being exclusive of or the relation
being separate from.
Platonic realism is also commonly referred to as simply Plato's theory of universals, just Platonism, or just realism. The latter two terms are problematic: the term
realism has several meanings both in philosophical and in non-philosophical fields and the term
Platonism refers to the entire philosophy of Plato and is often synonymous with
Platonic idealism. The two terms are common shorthand, nevertheless, in certain contexts where they are understood.
The theory is expounded in
The Republic and elsewhere, notably in the
Phaedo, the
Phaedrus, the
Meno, and the
Parmenides.
In Platonic realism,
universals do not exist in the way that ordinary physical objects exist, but were originally thought to have a sort of ghostly or heavenly mode of existence. However, more modern versions of the theory do not apply such potentially misleading descriptions to universals. Instead, such versions maintain that it is meaningless (or a
category mistake) to apply the categories of space and time to
universals.
Regardless their description, Platonic realism holds that
universals do exist in a broad, abstract sense, although not at any spatial or temporal distance from people's bodies. Thus, people cannot see or otherwise come into sensory contact with
universals, but in order to conceive of universals, one must be able to conceive of these abstract forms. Most modern Platonists avoid the possible ambiguity by never claiming that
universals exist, but "merely" that they
are.
Theories of universals
Theories of
universals, including Platonic realism, are challenged to satisfy the certain
constraints on theories of universals.
Of those constraints, Platonic realism strongly satisfies one, in that it is a theory of what general terms refer to.
Forms are ideal in supplying meaning to referents for general terms. That is, to understand terms such as
applehood and
redness, Platonic realism say that they refer to
forms. Indeed, Platonism gets much of its plausibility because mentioning
redness, for example, seems to be referring to something that is apart from space and time, but which has lots of specific instances.
Forms
One type of
universal defined by Plato is the
form or
idea. Although some versions of Platonic realism regard Plato's
forms as ideas in the mind of
God, most take
forms not to be mental entities at all, but rather
archetypes (original models) of which particular objects, properties, and relations are copies. Due to the potential confusion of the term
idea, philosophers usually use the terms
form,
Platonic form, or
universal.
In Platonic realism,
forms are related to
particulars (instances of objects and properties) in that a
particular is regarded as a
copy of its form. For example, a particular apple is said to be a
copy of the
form of
Applehood and the apple's redness is a
copy of the
form of
Redness.
Participation is another relationship between
forms and
particulars.
Particulars are said to
participate in the
forms, and the
forms are said to
inhere in the
particulars.
According to Plato, there are some
forms that are not instantiated at all, but, he contends, that does not imply that the forms
could not be instantiated.
Forms are capable of being instantiated by many different
particulars, which would result in the
form's having many copies, or
inhering many
particulars.
Two main criticisms with Platonic realism relate to
inherence and difficulty of creating concepts without sense-perception. Despite its criticisms, though, realism has strong defenders. Its popularity through the ages is cyclic.
Criticism of inherence
Critics claim that the terms
instantiation and
copy are not further defined and that
participation and
inherence are similarly mysterious and unenlightening.They question what it means to say that the
form of
applehood inheres a particular apple or that the apple is a
copy of the
form of
applehood. To the critic, it seems that the
forms, not being spatial, cannot have a shape, so it cannot mean be that the apple
is the same shape as the
form. Likewise, the critic claims it is unclear what it means to say that an apple
participates in
applehood.
Arguments refuting the
inherence criticism, however, claim that a
form of something spatial can lack a concrete (spatial) location and yet have
in abstracto spatial qualities. An apple, then, can have the same shape as its
form. Such arguments typically claim that the relationship between a
particular and its
form is very intelligible and easily grasped; that people unproblematically apply Platonic theory in everyday life; and that the
inherence criticism is only created by the artificial demand to explain the normal understanding of
inherence as if it were highly problematical. That is, the supporting argument claims that the criticism is with the mere illusion of a problem and thus could render suspect any philosophical concept.
Criticism of concepts without sense-perception
A criticism of
forms relates to the origin of concepts without the benefit of sense-perception. For example, to think of redness in general, according to Plato, is to think of the
form of redness. Critics, however, question how one can have the concept of a
form existing in a special realm of the universe, apart from space and time, since such a concept cannot come from sense-perception. Although one can see an apple and its redness, the critic argues, those things merely
participate in, or are
copies of, the
forms. Thus, they claim, to conceive of a particular apple and its redness is not to conceive of
applehood or
redness-in-general, so they question the source of the concept.
Plato's doctrine of recollection, however, addresses such criticism by saying that souls are
born with the concepts of the
forms, and just have to be
reminded of those concepts from back before birth, when the souls were in close contact with the
forms in the Platonic heaven. Plato is thus known as one of the very first
rationalists, believing as he did that humans are born with a fund of
a priori knowledge, to which they have access through a process of reason or intellection — a process that critics find to be rather mysterious.
A more modern response to the Platonic realism criticism of
concepts without sense-perception is the claim that the universality of its qualities is an unavoidable given because one only experiences an object by means of general concepts. So, since the critic already grasps the relation between the abstract and the concrete, he is invited to stop thinking that it implies a contradiction. The response reconciles Platonism with empiricism by contending that an abstract (and thus not real) object is
real and knowable by its instantiation. Since the critic has, after all, naturally understood the abstract, the response suggests merely to abandon prejudice and accept it.
*
Philosophy of mathematics*
Substance theory*
Truth*
Truth theory*
Universal (metaphysics)
