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?