None of us are rational economic men as we're supposed to be portrayed in economic theory where mixes of passions, of desires, of moral principles, of self-deception, of altruism, of concern of others, of concerns for ourselves and an interest in our bank accounts. And social policies have to be responsive to the complexity of who we are as people or else, like the war on drugs, they're simply going to fail.

Bentham spent much of his life writing constitutions and proposing legal reform in the light of his utilitarianism. The evaluation of particular acts was hardly his concern. The psychology of his day was hedonistic and he worked in that framework and passed it on to Mill, but it is clear as day that Mill was not a hedonist in the sense in which we use that term today, though he used the language of pleasure and pain to express his views.

People who go around saying that it is wrong to fly and to eat meat are not so much making appeals to us from within our shared morality, but engaging in something more like "persuasive definition." They want us to look at the world and ourselves in a different way. Someday these prohibitions against flying and eating meat may be written into our moral psychology, but it will only be after there are viable, widely shared alternatives that are beginning to be widely adopted.

The problem is that for almost any feature of humanity that you can name, whether it's the ability to suffer, whether it's the capacity to reason, whether it's having lives that can go better or worse, there are at least some other non-human animals that have all of these features as well. So to exclude non-human animals from the range of moral concern but to include all humans, just seems morally arbitrary.

Philosophers tend to radically underestimate the distance between abstract principles (such as "reduce suffering") and what it might actually mean for people to act on them.

If you look globally you see a patchwork of jurisdictions (nations, states, provinces, cities) that have taken aggressive action on climate change, and a patchwork of jurisdictions that have not. These various policies reflect the politics of each jurisdiction and the values of its citizens.

Some philosophers think that the idea of a consequentialist virtue theory is strange, but the real strength of consequentialism is that it can emulate the requirements of other moral theories when it is the case that acting on those theories would improve the world.