Meditations, Book 4, Section 29

Marcus Aurelius — The Emperor

Whatever exists right now, whatever has existed day by day — all the things we remember, and our minds and memories too — keep thinking about this: everything that exists changes and transforms. Train yourself to think about this often. The universe loves nothing more than changing what exists and making new things from the old. So we can say that everything now is just the seed of what will come next. If you think only plants and babies come from seeds, you're missing the point.

Marcus Aurelius — The Emperor Original

Whatsoever is now present, and from day to day hath its existence; all objects of memories, and the minds and memories themselves, incessantly consider, all things that are, have their being by change and alteration. Use thyself therefore often to meditate upon this, that the nature of the universe delights in nothing more, than in altering those things that are, and in making others like unto them. So that we may say, that whatsoever is, is but as it were the seed of that which shall be. For if thou think that that only is seed, which either the earth or the womb receiveth, thou art very simple.