13.  According to their condition.

We may, I think, from the make of an oyster or cockle, reasonably conclude that it has not so many, nor so quick senses as a man, or several other animals; nor if it had, would it, in that state and incapacity of transferring itself from one place to another, be bettered by them.  What good would sight and hearing do to a creature that cannot move itself to or from the objects wherein at a distance it perceives good or evil?  And would not quickness of sensation be an inconvenience to an animal that must lie still where chance has once placed it, and there receive the afflux of colder or warmer, clean or foul water, as it happens to come to it?

14.  Decay of perception in old age.

But yet I cannot but think there is some small dull perception, whereby they are distinguished from perfect insensibility.  And that this may be so, we have plain instances, even in mankind itself.  Take one in whom decrepit old age has blotted out the memory of his past knowledge, and clearly wiped out the ideas his mind was formerly stored with, and has, by destroying his sight, hearing, and smell quite, and his taste to a great degree, stopped up almost all the passages for new ones to enter; or if there be some of the inlets yet half open, the impressions made are scarcely perceived, or not at all retained.  How far such an one (notwithstanding all that is boasted of innate principles) is in his knowledge and intellectual faculties above the condition of a cockle or an oyster, I leave to be considered.  And if a man had passed sixty years in such a state, as it is possible he might, as well as three days, I wonder what difference there would be, in any intellectual perfections, between him and the lowest degree of animals.

15.  Perception the Inlet of all materials of Knowledge.

Perception then being the first step and degree towards knowledge, and the inlet of all the materials of it; the fewer senses any man, as well as any other creature, hath; and the fewer and duller the impressions are that are made by them; and the duller the faculties are that are employed about them,—­the more remote are they from that knowledge which is to be found in some men.  But this being in great variety of degrees (as may be perceived amongst men) cannot certainly be discovered in the several species of animals, much less in their particular individuals.  It suffices me only to have remarked here,—­that perception is the first operation of all our intellectual faculties, and the inlet of all knowledge in our minds.  And I am apt too to imagine, that it is perception, in the lowest degree of it, which puts the boundaries between animals and the inferior ranks of creatures.  But this I mention only as my conjecture by the by; it being indifferent to the matter in hand which way the learned shall determine of it.

CHAPTER X.