If somebody knew every time they did something it was going to be a hit there would never be any failures. Sadly, that's not how it works. You take nothing for granted.
Nature is seen by humans through a screen of beliefs, knowledge, and purposes, and it is in terms of their images of nature, rather than of the actual structure of nature, that they act. Yet, it is upon nature itself that they do act, and it is nature itself that acts upon them, nurturing or destroying them.