As all our ideas are derived ultimately from the senses, almost all the names we have for intellectual ideas, seem to be derived ultimately from the names of such objects as afford sensible ideas: that is, of objects that belong to one or other of the three classes Of real entities. Insomuch that, whether we perceive it or no, we can scarce express ourselves on any occasion but in metaphors. A most important discovery this in the metaphysical part of grammar, for which we seem to be indebted to M. d'Alembert. See his Melanges, tom. I, Disc. Prelim. &c.
The way in which the import of the word forfeiture is connected with sensible ideas seems to be as follows: the words to forfeit come either immediately, or through the medium of the old French, from the modern Latin word forisfacere. Foris means out of doors, or out of the house; facere, is to make or to cause to be. The conceit then is that, when any object is in a man's possession, it is as it were within doors; within his house; any act, therefore, which, in consequence of some operation of the law, has the effect of causing the object to be no longer in his possession, has the effect of causing it, as it were, to be out of his doors, and no longer within his house.RP Book 3 Chapter 1