n the thinker himself is the dross which must be refined away in
order to obtain the pure truth. When, then, in the critical epoch of the
Greek sophists, Protagoras declares that there is no belief that is not
of this character, his philosophy is promptly recognized as scepticism.
Protagoras argues that sense qualities are clearly dependent upon the
actual operations of the senses, and that all knowledge reduces
ultimately to these terms.

"The senses are variously named hearing, seeing, smelling;
there is the sense of heat, cold, pleasure, pain, desire,
fear, and many more which are named, as well as innumerable
others which have no name; _with each of them there is born an
object of sense_,--all sorts of colors born with all sorts of
sight and sounds in like manner with hearing, and other
objects with the other senses."[269:3]

If the objects are "born with" the senses, it follows that they are born
with and appertain to the individual perceiver.

"Either show, if you can, that our sensations are not
relative and individual, or, if you admit that they are
individual, prove that this does not involve the consequence
that the appearance becomes, or, if you like to say, is to the
individual only."[270:4]

The same motif is thus rendered by Walter Pater in the Conclusion of his
"Renaissance":

"At first sight experience seems to bury us under a flood of
external objects, pressing upon us with a sharp and
importunate reality, calling us out of ourselves in a thousand
forms of action. But when reflexion begins to act upon those
objects they are dissipated under its influence; the cohesive
force seems suspended like a trick of magic; each object is
loosed into a group of impressions--color, odor, texture--in
the mind of the observer. . . . Experience, already reduced to
a swarm of impressions, is ringed round for each one of us by
that thick wall of personality through which no real voice has
ever pierced on its way to us, or from us to that which we can
only conjecture to be without. Every one of these impressions
is the impression of the individual in his isolation, each
mind keeping as a solitary prisoner its own dream of a world."

The Protagorean generalization is due to the reflection that all
experience is some individual experience, that no subject of discourse
escapes the imputati