It must, then, necessarily be admitted that the existence of substance as its essence is an eternal truth.

And we can hence conclude by another process of reasoning--that there is but one such substance.

I think that this may profitably be done at once; and, in order to proceed regularly with the demonstration, we must premise:---- 1.

The true definition of a thing neither involves nor expresses anything beyond the nature of the thing defined.

From this it follows that---- 2.