it is impossible to mark the point of contact. Ideas of the same
race, though not exactly alike, are sometimes so little different,
that no words can express the dissimilitude, though the mind easily
perceives it, when they are exhibited together; and sometimes there
is such a confusion of acceptations, that discernment is wearied,
and distinction puzzled, and perseverance herself hurries to an
end, by crouding together what she cannot separate.

These complaints of difficulty will, by those that have never
considered words beyond their popular use, be thought only the jargon
of a man willing to magnify his labours, and procure veneration to
his studies by involution and obscurity. But every art is obscure
to those that have not learned it: this uncertainty of terms,
and commixture of ideas, is well known to those who have joined
philosophy with grammar; and if I have not expressed them very
clearly, it must be remembered that I am speaking of that which
words are insufficient to explain.

The original sense of words is often driven out of use by their
metaphorical acceptations, yet must be inserted for the sake of
a regular origination. Thus I know not whether ardour is used for
material heat, or whether flagrant, in English, ever signifies the
same with burning; yet such are the primitive ideas of these words,
which are therefore set first, though without examples, that the
figurative senses may be commodiously deduced.

Such is the exuberance of signification which many words have
obtained, that it was scarcely possible to collect all their senses;
sometimes the meaning of derivatives must be sought in the mother
term, and sometimes deficient explanations of the primitive may