The reason why I do it for you is that I hope you will do it for me in return.

2. Acting on conscience seems to have no biological benefits; If there is, only moral individuals can survive and reproduce. (para. 100). 30, Lesson 8)

It seems that it is impossible to do things according to conscience. If there are any benefits, only people with a sense of morality will survive and develop.

3. Survival of the fittest (Lesson 8)

Whoever is most suitable for the surrounding environment can survive.

I hope it helps you.