which he attaches to practical life, he is at variance with both of them.
To suppose that practice can be divorced from speculation, or that we may
do good without caring about truth, is by no means singular, either in
philosophy or life. The singularity of this, as of some other (so-called)
sophistical doctrines, is the frankness with which they are avowed, instead
of being veiled, as in modern times, under ambiguous and convenient
phrases.

Plato appears to treat Protagoras much as he himself is treated by
Aristotle; that is to say, he does not attempt to understand him from his
own point of view. But he entangles him in the meshes of a more advanced
logic. To which Protagoras is supposed to reply by Megarian quibbles,
which destroy logic, 'Not only man, but each man, and each man at each
moment.' In the arguments about sight and memory there is a palpable
unfairness which is worthy of the great 'brainless brothers,' Euthydemus
and Dionysodorus, and may be compared with the egkekalummenos ('obvelatus')
of Eubulides. For he who sees with one eye only cannot be truly said both
to see and not to see; nor is memory, which is liable to forget, the
immediate knowledge to which Protagoras applies the term. Theodorus justly
charges Socrates with going beyond the truth; and Protagoras has equally
right on his side when he protests against Socrates arguing from the common
use of words, which 'the vulgar pervert in all manner of ways.'

III. The theory of Protagoras is connected by Aristotle as well as Plato
with the flux of Heracleitus. But Aristotle is only following Plato, and
Plato, as we have already seen, did not mean to imply that such a connexion
was admitted by Protagoras himself. His metaphysical genius saw or seemed
to see a common tendency in them, just as the modern historian of ancient
philosophy might perceive a parallelism between two thinkers of which they
were probably unconscious themselves. We must remember throughout that