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.

If we compare a severely defective human infant with a nonhuman animal, a dog or a pig, for example, we will often find the nonhuman to have superior capacities, both actual and potential, for rationality, self-consciousness, communication and anything else that can plausibly be considered morally significant.

Should one break in and free the animals? That is illegal, but the obligation to obey the law is not absolute. It was justifiably broken by those who helped runaway slaves in the American South, to mention only one possible parallel.

There are a lot of weapons that we've developed which we've pulled back from - biological weapons, chemical weapons, etc. This may be the case with armed autonomous robotics, where we ultimately pull back from them.

Remember that not everyone is as strong as you are. Be mindful of human weakness, and of the fact that it may be more important, in the long run, to get many people taking steps in the right direction than to have fewer achieving the ideal.

If we're going to live an ethical life, it's not enough just to follow the thou-shalt-nots. … If we have enough, we have to share some of that with people who have so little.

If we all think only of our own interests, we are headed for collective disaster - just look at what we are doing to our planet's climate.