From the Beginning to Plato

FROM THE BEGINNING TO PLATO 135
What Parmenides says about his system of ‘opinions’ confirms the conclusion
already reached, that for him sense-perception cannot give knowledge. For he is
at pains to emphasize that such a system has no ‘proper guarantee of truth’; and
that it is ‘deceptive’ (it purports to give knowledge, but does not). It appeals to
empirical evidence for support, not to reason. So it lacks any claim to be an
object of knowledge. The deeper reason why it cannot be supported by appeal to
pure reason is presumably that it is concerned with ‘peripheral’, contingent
aspects of reality.
But there is still a problem. If conducted in the usual way, a cosmology must also
necessarily be not so much false as meaningless verbiage, since it takes seriously
the illusions of plurality and change, speaks as though they were real, and offers
explanations of such changes in terms of physical necessities. Parmenides’
‘Opinions’ is such a cosmology. Why does he deliberately offer a system of
which he himself thinks, and indeed implicitly says (in calling it ‘deceptive’, and
basing it on an ‘error’), that it is not merely not certain, but, taken literally,
meaningless all through?
One possible answer is that Parmenides thought that his convenient, but
literally meaningless, statements could be at need translated back into the correct
but cumbersome language of timelessness and logical monism. Unfortunately,
there is no indication in the text that it is merely a question of words.
He does at least seem to reassure us that, meaningless or not, these statements
are practically useful. In some way they correspond to the way the world
presents itself to us. The fictitious entities they mention correspond to the
fictions we create on the basis of our misread ordinary experience. That
experience shows they may be usefully manipulated to give a practically
workable understanding of the phenomenal world. 22 (Cosmology so conceived is
like science as seen by ‘operationalist’ philosophers of science; and like
divination and natural magic—a thought perhaps taken further by
Empedocles. 23 )
Within such limits, cosmology may none the less be required to satisfy certain
formal demands. 24 Parmenides sets out these demands explicitly, for the first
time. The original promise of the goddess stresses that the cosmology to be told
is (1) reliable; (2) comprehensive. Both of these points are echoed in the later
passage, (1) Reliability is echoed by ‘deceptive’ and ‘plausible’. The demands on
the cosmology are further that it be a ‘world-ordering’, not only (2)
comprehensive but also (3) coherent and formally pleasing; and (4) the best
possible of its kind. These last two points may also include economy or beauty
of explanation. The Principle of Sufficient Reason, which is closely related to the
demand for economy, appears, as in the exploration of reality, so again in the
cosmology, to yield a symmetry between the two cosmic components.
In fact, Parmenides devises an elegant and economical basis for cosmology by
following a hint given by the ‘way of mortals’. Any conventional cosmology has
to tread that false way, and to say both ‘it is’ and ‘it is not’. The simplest way to
commit this error is to suppose initially not one logical subject but two: one