If we consider the essence of things, whether existing or non-existing, we discover that it neither involves existence nor duration, and therefore the essence of existing things cannot be the cause of their existence nor of their duration, but God only is the cause, to whose nature alone existence pertains.
Spinoza here contradicts evolutionary theory which holds that things (species) have no essence, and that the value of a species is a function of its duration and its ability to transform itself into other species.
