What now matters most is that we avoid ending human history. If there are no rational beings elsewhere, it may depend on us and our successors whether it will all be worth it, because the existence of the Universe will have been on the whole good.

This part of Kant’s view is, I believe, a profound truth. We can be morally responsible in several other ways, or senses, but no one could ever be responsible, I believe, in any way that could make them deserve to suffer. Nor, I believe, does anyone deserve to be less happy.

If there were no such normative truths, nothing would matter, and we would have no reasons to try to decide how to live. Such decisions would be arbitrary. We would not be the animals that can understand and respond to reasons. In a world without reasons, we would act only on our instincts and desires, living as other animals live. The Universe would not contain rational beings.

What am I more than elaborate sentience?

Criticizing himself again, Sidgwick writes: I am not an original man: and I think less of my own thoughts every day.

We ought not to do to our future selves what it would be wrong to do to other people.

Normativity, I believe, is very different from motivating force. Neither includes, or implies, the other. Other animals can be motivated by their desires and beliefs. Only we can understand and respond to reasons.

No question is more sublime than why there is a Universe: why there is anything rather than nothing.

We might neglect our future selves because of some failure of belief or imagination.

My life seemed like a glass tunnel, through which I was moving faster every year, and at the end of which there was darkness. When I changed my view, the walls of my glass tunnel disappeared. I now live in the open air.