Sin lies only in hurting other people unnecessarily. All other "sins" are invented nonsense. (Hurting yourself is not sinful - just stupid).

I am free, no matter what rules surround me. If I find them tolerable, I tolerate them; if I find them too obnoxious, I break them. I am free because I know that I alone am morally responsible for everything I do.

The instinct to survive is human nature itself, and every aspect of our personalities derives from it. Anything that conflicts with the survival instinct acts sooner or later to eliminate the individual and thereby fails to show up in future generations. . . . A scientifically verifiable theory of morals must be rooted in the individual's instinct to survive--and nowhere else!--and must correctly describe the hierarchy of survival, note the motivations at each level, and resolve all conflicts.
We have such a theory now; we can solve any moral problem, on any level. Self-interest, love of family, duty to country, responsibility toward the human race . . . .
The basis of all morality is duty, a concept with the same relation to group that self-interest has to individual.

Elephants aren't human but they are very nice people.

People usually believe anything that they are told early and often.

Never tease an old dog; he might have one bite left.