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.

Charitable giving is a huge sector in the United States. It amounts to $350 billion a year. And yet, I can't help feeling that a lot of that is wasted because people have not been thinking about how to do it as effectively as possible.

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.

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.

If penicillin had been judged by its toxicity to guinea pigs, it might never have been used by man.

What one generation finds ridiculous, the next accepts; and the third shudders when it looks back on what the first did.

When fish experience something that would cause other animals physical pain, they behave in ways suggestive of pain, and the change in behaviour may last several hours.