Gottfried leibniz

Men act like brutes in so far as the sequences of their perceptions arise through the principle of memory only, like those empirical physicians who have mere practice without theory.

There are also two kinds of truths: truth of reasoning and truths of fact. Truths of reasoning are necessary and their opposite is impossible; those of fact are contingent and their opposite is...

It follows from what we have just said, that the natural changes of monads come from an internal principle, since an external cause would be unable to influence their inner being.

Whence it follows that God is absolutely perfect, since perfection is nothing but magnitude of positive reality, in the strict sense, setting aside the limits or bounds in things which are limited.

Finally there are simple ideas of which no definition can be given; there are also axioms or postulates, or in a word primary principles, which cannot be proved and have no need of proof.

Now where there are no parts, there neither extension, nor shape, nor divisibility is possible. And these monads are the true atoms of nature and, in a word, the elements of things.

I also take it as granted that every created thing, and consequently the created monad also, is subject to change, and indeed that this change is continual in each one.

For since it is impossible for a created monad to have a physical influence on the inner nature of another, this is the only way in which one can be dependent on another.

When a truth is necessary, the reason for it can be found by analysis, that is, by resolving it into simpler ideas and truths until the primary ones are reached.

It can have its effect only through the intervention of God, inasmuch as in the ideas of God a monad rightly demands that God, in regulating the rest from the beginning of things, should have regard...