inaSHvity of Matter, &c. 191

ter alike; then such perception ought to beas mechanical and necessary as the action ofmatter upon matter is. And because actionand re-aBion are equal, the perception oughtto be excited equally in both the matter aid-ing, and the matter aEted upon. The percep-tion ought to be strong according to the forceof the collision: nothing but no force at allcould produce no perception at all; but inall other cases the perception should be some-thing. But these consequences are absurd,and false; and therefore the supposition fromwhich they follow must be so too. In amortified or gangren’d limb we have no per- 1ception,though it be touched or even cut off.It must be organically united to the percipientbeing in us, that perception may be excitedby the action of other matter upon it. We hadperception of the action of other matter uponthat part before, but have it not now, when theorganism is vitiated; which strews that someother thing is necessary besides the action ofmatter upon matter. When we touch thehair of our head,action and re-action beingequal, the perception ought to be as strongthere as in the other part: so if the fingerstrikes against the eye, or any fore or wound-I ed