Meditations IV.36

Unceasingly contemplate the generation of all things through change, and accustom thyself to the thought that the Nature of the Universe delights above all in changing the things that exist and making new ones of the same pattern. For in a manner everything that exists is the seed of that which shall come out of it. But thou imaginest that only to be seed that is deposited in the earth or the womb, a view beyond measure unphilosophical.