Mainly things regarding virtues and values of human relationships and character. There are languages and mathematics, logic and, like you said intuition, and reason.
I think there are true forms of justice and truth according to virtues. I talk about virtues all the time so I don't want to sound like a broken record. Virtues can be studied and defined in great depth. The capacity to be fair and just is apart of human potential. There are foundations to what is deserving and trustworthy. There are general principles and understandings that lead to good will, trust, and a worthy love. The hearts of human beings have potentials, and capacities for great things.
In short I sense there are rules for living a good life, and dealing with evils, and troubles that can happen. I don't think truth is an exhaustible study; there's a lot of wisdom to be learned over the course of a lifetime.