I observe that my senses of sight, smell, touch, taste, and hearing constitute my comprehension of the infinite universe of swerving atoms. The natural universe is observable and relevant to me, the unnatural is unobservable and therefore irrelevant to me.
I observe that newborns and animals seek pleasure and avoid pain. We at least need water, food, shelter, friends, and wisdom. Nature provides water, food, shelter, friends, and wisdom.
I observe that by using my senses, remembering past pleasures, and consulting frankly with my friends, I can make wise decisions to cultivate my happiness. This is a natural and good way to live.