30. The Difficulty from ill Use of Names.
To conclude: Whatever substance begins to exist, it must, during its existence, necessarily be the same: whatever compositions of substances begin to exist, during the union of those substances, the concrete must be the same: whatsoever mode begins to exist, during its existence it is the same: and so if the composition be of distinct substances and different modes, the same rule holds. Whereby it will appear, that the difficulty or obscurity that has been about this matter rather rises from the names ill-used, than from any obscurity in things themselves. For whatever makes the specific idea to which the name is applied, if that idea be steadily kept to, the distinction of anything into the same and divers will easily be conceived, and there can arise no doubt about it.
31. Continuance of that which we have made to be our complex idea of man makes the same man.
For, supposing a rational spirit be the idea of a man, it is easy to know what is the same man, viz. the same spirit—whether separate or in a body—will be the same man. Supposing a rational spirit vitally united to a body of a certain conformation of parts to make a man; whilst that rational spirit, with that vital conformation of parts, though continued in a fleeting successive body, remains, it will be the same man. But if to any one the idea of a man be but the vital union of parts in a certain shape; as long as that vital union and shape remain in a concrete, no otherwise the same but by a continued succession of fleeting particles, it will be the same man. For, whatever be the composition whereof the complex idea is made, whenever existence makes it one particular thing under any denomination, the same existence continued preserves it the same individual under the same denomination.
CHAPTER XXVIII.
Of other relations.
1. Ideas of Proportional relations.