for clear
and fair deductions from those principles: and sometimes for the cause,
and particularly the final cause. But the consideration I shall have of
it here is in a signification different from all these; and that is, as
it stands for a faculty in man, that faculty whereby man is supposed
to be distinguished from beasts, and wherein it is evident he much
surpasses them.

2. Wherein Reasoning consists.

If general knowledge, as has been shown, consists in a perception of the
agreement or disagreement of our own ideas, and the knowledge of
the existence of all things without us (except only of a God, whose
existence every man may certainly know and demonstrate to himself from
his own existence), be had only by our senses, what room is there
for the exercise of any other faculty, but OUTWARD SENSE and INWARD
PERCEPTION? What need is there of REASON? Very much: both for the
enlargement of our knowledge, and regulating our assent. For it hath to
do both in knowledge and opinion, and is necessary and assisting to all
our other intellectual faculties, and indeed contains two of them, viz.
SAGACITY and ILLATION. By the one, it finds out; and by the other, it so
orders the intermediate ideas as to discover what connexion there is
in each link of the chain, whereby the extremes are held together; and
thereby, as it were, to draw into view the truth sought for, which is
that which we call ILLATION or INFERENCE, and consists in nothing but
the perception of the connexion there is between the ideas, in each step
of the deduction; whereby the mind comes to see, either the certain
agreement or disagreement of any two ideas, as in demonstration, in
which it arrives at KNOWLEDGE; or their probable connexion, on which it
gives or withholds its assent, as in OPINION. Sense and intuition reach
but a very little way. The greatest part of our knowledge depends upon
deductions and intermediate ideas: and in those cases where we are fain
to substitute assent instead of knowledge, and take propositions for
true, without being certain they are so, we have need to find out,
examine, and compare the grounds of their probability. In both these
cases, the faculty which finds out the means, and rightly applies them,
to discover certainty in the one, and probability in the other, is
that which we call REASON. For, as reason perceives the necessary and
indubitable connexion of all the ideas or proofs one to another, in
each step of any demons