PHIL. But, doth it in like manner depend on YOUR will that in looking on this flower you perceive WHITE rather than any other colour? Or, directing your open eyes towards yonder part of the heaven, can you avoid seeing the sun? Or is light or darkness the effect of your volition? HYL. No, certainly. PHIL. You are then in these respects altogether passive? HYL. I am. PHIL. Tell me now, whether SEEING consists in perceiving light and colours, or in opening and turning the eyes? HYL. Without doubt, in the former. PHIL. Since therefore you are in the very perception of light and colours altogether passive, what is become of that action you were speaking of as an ingredient in every sensation? And, doth it not follow from your own concessions, that the perception of light and colours, including no action in it, may exist in an unperceiving substance? And is not this a plain contradiction? HYL. I know not what to think of it. PHIL. Besides, since you distinguish the ACTIVE and PASSIVE in every perception, you must do it in that of pain. But how is it possible that pain, be it as little active as you please, should exist in an unperceiving substance? In short, do but consider the point, and then confess ingenuously, whether light and colours, tastes, sounds, &c. are not all equally passions or sensations in the soul. You may indeed call them EXTERNAL OBJECTS, and give them in words what subsistence you please. But, examine your own thoughts, and then tell me whether it be not as I say? HYL. I acknowledge, Philonous, that, upon a fair observation of what passes in my mind, I can discover nothing else but that I am a thinking being, affected with variety of sensations; neither is it possible to conceive how a sensation should exist in an unperceiving substance. But then, on the other hand, when I look on sensible things in a different view, considering them as so many modes and qualities, I find it necessary to suppose a MATERIAL SUBSTRATUM, without which they cannot be conceived to exist. PHIL. MATERIAL SUBSTRATUM call you it? Pray, by which of your senses came you acquainted with that being? HYL. It is not itself sensible; its modes and qualities only being perceived by the senses. PHIL. I presume then it was by reflexion and reason you obtained the idea of it? HYL. I do not pretend to any proper positive IDEA of it. However, I conclude it exists, because qualities cannot be conceived to exist without a support. PHIL. It seems then you have only a relative NOTION of it, or that you conceive it not otherwise than by conceiving the relation it bears to sensible qualities? HYL. Right. PHIL. Be pleased therefore to let me know wherein that relation consists. HYL. Is it not sufficiently expressed in the term SUBSTRATUM, or SUBSTANCE? PHIL. If so, the word SUBSTRATUM should import that it is spread under the sensible qualities or accidents? HYL. True. PHIL. And consequently under extension? HYL. I own it.