If you go back in time you'll find tribes that were essentially only concerned with their own tribal members. If you were a member of another tribe, you could be killed with impunity.

Unfortunately for ethical egoism, the claim that we will all be better off if every one of us does what is in his or her own interest is incorrect. This is shown by what are known as "prisoner's dilemma" situations, which are playing an increasingly important role in discussions of ethical theory... At least on the collective level, therefore, egoism is self-defeating - a conclusion well brought out by Parfit in his aforementioned Reasons and Persons.

If you have the abilities to earn a lot of money and if you have the character to persist in giving that to the most effective charities you can find, then that may be the best thing that you can do. And - also, if you do become a Wall Street banker, I think you need to be aware of what you're doing in terms of your daily work, not just earning money to give a lot away. But you need to think about - am I harming people through the work that I'm doing?

We see things like reciprocity which are fairly central to our view of ethics. But if you're talking about a set of worked-out rules on what we are supposed to do then, yes, it is a human product.

So, basically, my view is I don't want to support the exploitation of animals, and within reason, I will do what I can to avoid it, but it's not like it's a religion for me. It's not like I consider I'm polluted if somehow some bit of milk or cheese or something passes my lips.

Effective altruism is the form of altruism in which we bring our rational capacities to bear in order to do the most good that we can.

If it is in our power to prevent something bad from happening, without thereby sacrificing anything of comparable moral importance, we ought, morally, to do it.