We have already followed the fortunes of that empirical subjectivism which issues from the relativity of perception. At the very dawn of philosophy it was observed that what is seen, heard, or otherwise experienced through the senses, depends not only upon the use of sense-organs, but upon the special point of view occupied by each individual sentient being. It was therefore concluded that the perceptual world belonged to the human knower with his limitations and perspective, rather than to being itself. It was this epistemological principle upon which Berkeley founded his empirical idealism. Believing knowledge to consist essentially in perception, and believing perception to be subjective, he had to choose between the relegation of being to a region inaccessible to knowledge, and the definition of being in terms of subjectivity. To avoid scepticism he accepted the latter alternative. But among the Greeks with whom this theory of perception originated, it drew its meaning in large part from the distinction between perception and reason. Thus we read in Plato's "Sophist": "And you would allow that we participate in generation with the body, and by perception; but we participate with the soul by thought in true essence, and essence you would affirm to be always the same and immutable, whereas generation varies."[370:8] It is conceived that although in perception man is condemned to a knowledge conditioned by the affections and station of his body, he may nevertheless escape himself and lay hold on the "true essence" of things, by virtue of thought. In other words, knowledge, in contradistinction to "opinion," is not made by the subject, but is the soul's participation in the eternal natures of things. In the moment of insight the varying course of the individual thinker coincides with the unvarying truth; but in that moment the individual thinker is ennobled through being assimilated to the truth, while the truth is no more, no less, the truth than before. [Sidenote: The Principle of Subjectivism Extended to Reason.]