I was wondering if it would be possible to help clear this section up:

However, the internal necessity perpetually to be, is inseparably connected with the necessity always to have been, and so the expression may stand as it is. “Gigni de nihilo nihil; in nihilum nil posse reverti,”30 are two propositions which the ancients never parted, and which people nowadays sometimes mistakenly disjoin, because they imagine that the propositions apply to objects as things in themselves, and that the former might be inimical to the dependence (even in respect of its substance also) of the world upon a supreme cause. The quote is from The Critique of Pure Reason, First Analogy, Principle of the Permanence of Substance.

I think they’re saying this:

• The idea of something being permanent means it has always been and always will be.
• You can’t seperate these two ideas: permanence requires both.
• People at the time of writing sometimes try to remove the “always has been” part as it conflicts with or removes the need for a creator (something which is permanent that created non-permanent things).
• These people applied the idea of permanence to things in themselves as if it were possible to perceive things in themselves, rather than their representations.

I suspect I could be wildly off here.