to your principles (since the motions perceived are both really in the
object) it is possible one and the same body shall be really moved the
same way at once, both very swift and very slow. How is this consistent
either with common sense, or with what you just now granted?

HYL. I have nothing to say to it.

PHIL. Then as for SOLIDITY; either you do not mean any sensible
quality by that word, and so it is beside our inquiry: or if you do, it
must be either hardness or resistance. But both the one and the other are
plainly relative to our senses: it being evident that what seems hard to
one animal may appear soft to another, who hath greater force and
firmness of limbs. Nor is it less plain that the resistance I feel is not
in the body.

HYL. I own the very SENSATION of resistance, which is all you
immediately perceive, is not in the body; but the CAUSE of that
sensation is.

PHIL. But the causes of our sensations are not things immediately
perceived, and therefore are not sensible. This point I thought had been
already determined.

HYL. I own it was; but you will pardon me if I seem a little
embarrassed: I know not how to quit my old notions.

PHIL. To help you out, do but consider that if EXTENSION be once
acknowledged to have no existence without the mind, the same must
necessarily be granted of motion, solidity, and gravity; since they all
evidently suppose extension. It is therefore superfluous to inquire