¶ … Philonus and Hylas discuss the issue of skepticism and its meaning. Philonus is presented as the Skeptic from the first, while Hylas sees himself as a realist. However, Philonus suggests that Hylas is wrong and that he (Philonus) can demonstrate that Hylas is actually a skeptic. Hylas does not believe this is possible, yet Philonus proceeds to guide the argument so that he does prove just what he says he can prove.
The discussion beings when Hylas asks if it is not true that Philonus has expressed the view that there is no such thing in the world as material substance. Philonus says he did not say that, and that what he did say is that there is no such thing as what philosophers call material substance in this world. This is the skeptical position Hylas sees him as taking, and Hylas states that he can think of nothing that would be more against common sense than to state that there is no such thing as matter. It is this statement which Philonus says he will use to show that Hylas is the true skeptic.
Philonus wants to establish what Hylas means by a skeptic, and Hylas answers that a skeptic is someone who doubts of everything. The individual is not a skeptic, then, if he has no doubts. Doubting is also described as standing between the positive and the negative, meaning not being sure which is correct. Philonus seizes on this to suggest that Hylas ha made an error in challenging Philonus's view that there is no matter and claiming it is skepticism. If Philonus asserts that there is no matter, he is taking a clear stand on the issue and so cannot be said to be skeptical, for if he...
What Hylas means is that a skeptic is one who denies the evidence of his senses, and since the senses say that matter is a real thing, then the skeptic is denying reality. When Hylas refers to sensible things, he apparently means only those things which can be perceived immediately by the senses. Philonus challenges such a simple definition, and Hylas again backtracks and restates his definition.
Philonus guides the conversation to show that what we perceive, the states we perceive, may or may not be in the objects we perceive, but in any case they cannot be perceived without the presence and participation of the mind. Philonus suggests that any opinion which leads to an absurdity cannot be true and yet he shows that based on what Hylas has said, an object may be hot and cold at the same time, which is absurd.
What Philonus shows in his analysis is that sensory perceptions involve imprecise definitions and cannot be trusted to provide clear proof of the existence or nature of anything. Instead, all that the individual can know is that in some way the external world causes the mind to react to stimuli and to determine various states on that basis. The skeptical position is that our senses mislead us, perhaps in every way possible so that we can never know what is real in the world and what is not. Philonus leads Hylas to the position that nothing then can be…
