Hyl. I do not sufficiently understand you.
Phil. In reading a book, what I immediately perceive [pg 383] are the letters; but mediately, or by means of these, are suggested to my mind the notions of God, virtue, truth, &c. Now, that the letters are truly sensible things, or perceived by sense, there is no doubt: but I would know whether you take the things suggested by them to be so too.
Hyl. No, certainly: it were absurd to think God or virtue sensible things; though they may be signified and suggested to the mind by sensible marks, with which they have an arbitrary connexion.
Phil. It seems then, that by sensible things you mean those only which can be perceived immediately by sense?
Hyl. Right.
Phil. Doth it not follow from this, that though I see one part of the sky red, and another blue, and that my reason doth thence evidently conclude there must be some cause of that diversity of colours, yet that cause cannot be said to be a sensible thing, or perceived by the sense of seeing?
Hyl. It doth.
Phil. In like manner, though I hear variety of sounds, yet I cannot be said to hear the causes of those sounds?
Hyl. You cannot.
Phil. And when by my touch I perceive a thing to be hot and heavy, I cannot say, with any truth or propriety, that I feel the cause of its heat or weight?