(_a_) “How that should be a right definition of liberty, which
comprehends neither the genus nor the difference, neither the matter nor
the form of liberty, &c: how a real faculty or the elective power,
should be defined by a negation or by an absence: is past my
understanding, and contrary to all the rules of right reason which I
have learned.” A right definition is that which determineth the
signification of the word defined, to the end that in the discourse
where it is used, the meaning of it may be constant and without
equivocation. This is the measure of a definition, and intelligible to
an English reader. But the Bishop, that measures it by the genus and the
difference, thinks, it seems, though he write English, he writes not to
an English reader unless he also be a Schoolman. I confess the rule is
good, that we ought to define, when it can be done, by using first some
more general term, and then by restraining the signification of that
general term, till it be the same with that of the word defined. And
this general term the School calls _genus_, and the restraint
_difference_. This, I say, is a good rule where it can be done; for some
words are so general, that they cannot admit a more general in their
definition. But why this ought to be a law of definition, I doubt it
would trouble him to find the reason; and therefore I refer him (he
shall give me leave sometimes to cite, as well as he,) to the fourteenth
and fifteenth articles of the sixth chapter of my book _De Corpore_. But
it is to little purpose that he requires in a definition so exactly the
genus and the difference, seeing he does not know them when they are
there. For in this my definition of liberty, the genus is absence of
impediments to action; and the difference or restriction is that they be
not contained in the nature of the agent. The Bishop therefore, though
he talk of genus and difference, understands not what they are, but
requires the matter and form of the thing in the definition. Matter is
body, that is to say, corporeal substance, and subject to dimension,
such as are the elements, and the things compounded of the elements. But
it is impossible that matter should be part of a definition, whose parts
are only words; or to put the name of matter into the definition of
liberty, which is immaterial. “How a real faculty can be defined by an
absence, is”, saith he, “past my understanding.” Unless he mean by _real
faculty_ a _very faculty_, I know not how a faculty is real. If he mean
so, then a very absence is as real as a very faculty. And if the word
defined signify an absence or negation, I hope he would not have me
define it by a presence or affirmation. Such a word is liberty; for it
signifieth freedom from impediments, which is all one with the absence
of impediments, as I have defined it. And if this be contrary to all the
rules of right reason, that is to say, of logic, that he hath learned, I
should advise him to read some other logic than he hath yet read, or
consider better those he did read when he was a young man and could less
understand them. He adds, that “by this definition, a stone hath liberty
to ascend into the air, because there is no outward impediment to hinder
it”. How knows he whether there be impediments to hinder it or not?
Certainly if a stone were thrown upwards, it would either go upwards
eternally, or it must be stopped by some outward impediment, or it must
stop itself. He hath confessed, that nothing can move itself; I doubt
not therefore that he will confess also, that it cannot stop itself. But
stopped we see it is; it is therefore stopped by impediments external.
He hath in this part of his answer ventured a little too far in speaking
of definition, and of impediments, and motion; and bewrayed too much his
ignorance in logic and philosophy; and talked so absurdly of the current
of rivers, and of the motion of the seas, and of the weight of water,
that it cannot be corrected otherwise than by blotting it all out.