To be honest there really is nothing to be the base of anything, if we dont take religion as base. Since religion is a given idea by a being which is ontologically higher than us, it is logical to base everthing on it; but first you have to accept it, where the problem begins.
This mat seem too much skeptic, indeed radically skeptic but you can not justify any premise you make. Even the basic logic like, a is equal to a. Many things may seem intuitionally true but when you try to justify it, you cant.
But here we are, i have a stomach which wants food, i have a mouth which wants to talk, i have dick/pussy which wants to fuck. We are a society, and we are here, we want to be together. So we need some limits to live together. Thats how we create our fucking morals.
a is equal to a only because we define it to be. Bad example tbh.