and the sensation of whiteness; the eye is filled with seeing, and becomes
not sight but a seeing eye, and the object is filled with whiteness, and
becomes not whiteness but white; and no other compound of either with
another would have produced the same effect. All sensation is to be
resolved into a similar combination of an agent and patient. Of either,
taken separately, no idea can be formed; and the agent may become a
patient, and the patient an agent. Hence there arises a general reflection
that nothing is, but all things become; no name can detain or fix them.
Are not these speculations charming, Theaetetus, and very good for a person
in your interesting situation? I am offering you specimens of other men's
wisdom, because I have no wisdom of my own, and I want to deliver you of
something; and presently we will see whether you have brought forth wind or
not. Tell me, then, what do you think of the notion that "All things are
becoming"?'

'When I hear your arguments, I am marvellously ready to assent.'

'But I ought not to conceal from you that there is a serious objection
which may be urged against this doctrine of Protagoras. For there are
states, such as madness and dreaming, in which perception is false; and
half our life is spent in dreaming; and who can say that at this instant we
are not dreaming? Even the fancies of madmen are real at the time. But if
knowledge is perception, how can we distinguish between the true and the
false in such cases? Having stated the objection, I will now state the
answer. Protagoras would deny the continuity of phenomena; he would say
that what is different is entirely different, and whether active or passive
has a different power. There are infinite agents and patients in the
world, and these produce in every combination of them a different
perception. Take myself as an instance:--Socrates may be ill or he may be
well,--and remember that Socrates, with all his accidents, is spoken of.