P6: Each thing, as far as it can by its own power, strives to persevere in its being.

Dem.: For singular things are modes by which God/Nature’s attributes are expressed in a certain and determinate way (by IP25 C), i.e. (by IP34), things that express, in a certain and determinate way, God/Nature’s power, by which God/Nature is and acts. And no thing has anything in itself by which it can be destroyed, or which takes its existence away (by P4). On the contrary, it is opposed to everything which can take its existence away (by P5). Therefore, as far as it can, and it lies in itself, it strives to persevere in its being, q.e.d.