Inconsistency of Plato's argument in the Sophistês. He says that the Sophist is a disputatious man who challenges every one for speaking falsehood. He says also that the Sophist is one who maintains false propositions to be impossible 220 Reasoning of Plato about Non-Ens--No predications except identical 221 Misconception of the function of the copula in predication _ib._ No formal Grammar or Logic existed at that time. No analysis or classification of propositions before the works of Aristotle 222 Plato's declared purpose in the Sophistês--To confute the various schools of thinkers--Antisthenes, Parmenides, the Materialists, &c. 223 Plato's refutation throws light upon the doctrine of Antisthenes _ib._ Plato's argument against the Materialists 224 Reply open to the Materialists _ib._ Plato's argument against the Idealists or Friends of Forms. Their point of view against him 225 Plato argues--That to know, and be known, is action and passion, a mode of relativity 226 Plato's reasoning--compared with the points of view of both _ib._ The argument of Plato goes to an entire denial of the Absolute, and a full establishment of the Relative 227 Coincidence of his argument with the doctrine of Protagoras in the Theætêtus _ib._ The Idealists maintained that Ideas or Forms were entirely unchangeable and eternal. Plato here denies this, and maintains that ideas were partly changeable, partly unchangeable 228 Plato's reasoning against the Materialists _ib._ Difference between Concrete and Abstract, not then made conspicuous. Large meaning here given by Plato to Ens--comprehending not only objects of Perception, but objects of Conception besides 229 Narrower meaning given by Materialists to Ens--they included only Objects of Perception. Their reasoning as opposed to Plato _ib._ Different definitions of Ens--by Plato--the Materialists, the Idealists 231 Plato's views about Non-Ens examined _ib._ His review of the select Five Forms 233 Plato's doctrine--That Non-Ens is nothing more than different from Ens _ib._ Communion of Non-Ens with proposition--possible and explicable 235 Imperfect analysis of a proposition--Plato does not recognise the predicate _ib._ Plato's explanation of Non-Ens is not satisfactory--Objections to it 236 Plato's view of the negative is erroneous. Logical maxim of contradiction 239 Examination of the illustrative propositions chosen by Plato--How do we know that one is true, the other false? _ib._ Necessity of accepting the evidence of sense 240 Errors of Antisthenes--depended partly on the imperfect formal logic of that day 241 Doctrine of the Sophistês--contradicts that of other Platonic dialogues 242 The persons whom Plato here attacks as Friends of Forms are those who held the same doctrine as Plato himself espouses in Phædon, Republic, &c. 246 The Sophistês recedes from the Platonic point of view, and approaches the Aristotelian 247