Here's the opening to Monadology. It seems to me striking to what degree W's logical atomism follows the same path. 1. The monad, of which we will speak here, is nothing else than a simple substance which goes to make up composites; by simple, we means without parts. 2. There must be simple substances because there are composites; for a composite is nothing but a collection oraggregatum of simple substances. 3. Now where there are no constituent parts there is possible neither extension, nor form, nor divisibility. These monads are the true atoms of nature, and, in fact, the elements of things. 4. Their dissolution, therefore, is not to be feared, and there is no way conceivable by which a simple substance can perish through natural means. 5. For the same reason there is no way conceivable by which a simple substance might, through natural means, come into existence, since it cannot be formed by composition. 6. We may say then, that the existence of monads can begin or end only all at once, that is to say, the monad can begin only through creation and end only through annihilation. Composites, however begin or end gradually. 7. There is also no way of explaining how a monad can be altered or changed in its inner being by any other created thing, since there is no possibility of transposition within it, nor can we conceive of any internal movement which can be produced, directed, increased or diminished there within the substance, such as can take place in the case of composites where a change can occur among the parts. The monads have no windows through which anything may come in or go out. The attributes are not liable to detach themselves and make an excursion outside the substance, as could sensible species of the schoolmen. In the same way neither substance nor attribute can enter from without into a monad. However, in my view, W's argument is more audacious both than this and than arguments for epistemic foundationalism. Leibniz can hold that there are simples in nature even if nobody can (or has yet) drilled down to them: that may be a scientific goal, but there's no reason to suppose that just because any such simples do (or even must) exist, that anybody has become acquainted with any. And the foundationalist who says that if we have evidence for anything we must have evidence for some things that don't require any additional evidence will generally provide examples (perhaps "This looks red to me" or "1 + 1 = 2" or "I exist" or "Red patch here.") But W can neither give examples nor claim that nobody need be acquainted with atomic facts. Why? Because in his view for anybody to understand anything there must be basic facts, and, since understanding is a cognitive activity it is implausible that atomic facts could do the work he requires of them if nobody was ever acquainted with one. That's why, IMHO, this is the most audacious philosophical argument since Anselm. W