Even if moral truths cannot affect people, they can still be truths. — Derek Parfit

"What now matters most is how we respond to various risks to the survival of humanity. We are creating some of these risks, and we are discovering how we could respond to these and other risks. If we reduce these risks, and humanity survives the next few centuries, our descendants or successors could end these risks by spreading through this galaxy. Life can be wonderful as well as terrible, and we shall increasingly have the power to make life good. Since human history may be only just beginning, we can expect that future humans, or supra-humans, may achieve some great goods that we cannot now even imagine. In Nietzsche’s words, there has never been such a new dawn and clear horizon, and such an open sea. If we are the only rational beings in the Universe, as some recent evidence suggests, it matters even more whether we shall have descendants or successors during the billions of years in which that would be possible. Some of our successors might live lives and create worlds that, though failing to justify past suffering, would have given us all, including those who suffered most, reasons to be glad that the Universe exists."

"Until this century, most of mankind lived in small communities. What each did could affect only a few others. But conditions have now changed. Each of us can now, in countless ways, affect countless other people. We can have real though small effects on thousands or millions of people. When these effects are widely dispersed, they may be either trivial, or imperceptible. It now makes a great difference whether we continue to believe that we cannot have greatly harmed or benefited others unless there are people with obvious grounds for resentment or gratitude."

"One thing that greatly matters is the failure of we rich people to prevent, as we so easily could, much of the suffering and many of the early deaths of the poorest people in the world. The money that we spend on an evening’s entertainment might instead save some poor person from death, blindness, or chronic and severe pain. If we believe that, in our treatment of these poorest people, we are not acting wrongly, we are like those who believed that they were justified in having slaves. Some of us ask how much of our wealth we rich people ought to give to these poorest people. But that question wrongly assumes that our wealth is ours to give. This wealth is legally ours. But these poorest people have much stronger moral claims to some of this wealth. We ought to transfer to these people […] at least ten per cent of what we inherit or earn."

"Take a Swede who is proud of his country’s peaceful record. He might have a similar divided attitude. He may not be disturbed by the thought that Sweden once fought aggressive wars; but if she had recently fought such wars he would be greatly disturbed. Someone might say, “This man’s attitude is indefensible. The wars of Gustavus, or of Karl XII, are as much part of Swedish history.” This truth cannot, I think, support this criticism. Modern Sweden is indeed continuous with the aggressive Sweden of the Vasa kings. But the connections are weak enough to justify this man’s attitude."

"Is the truth depressing? Some may find it so. But I find it liberating, and consoling. When I believed that my existence was a further fact, I seemed imprisoned in myself. 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. There is still a difference between my life and the lives of other people. But the difference is less. I am less concerned about the rest of my own life, and more concerned about the lives of others."

"Certain actual sleeping pills cause retrograde amnesia. It can be true that, if I take such a pill, I shall remain awake for an hour, but after my night’s sleep I shall have no memories of the second half of this hour. I have in fact taken such pills, and found out what the results are like. Suppose that I took such a pill nearly an hour ago. The person who wakes up in my bed tomorrow will not be psychologically continuous with me as I was half an hour ago. I am now on psychological branch-line, which will end soon when I fall asleep. During this half-hour, I am psychologically continuous with myself in the past. But I am not now psychologically continuous with myself in the future. I shall never later remember what I do or think or feel during this half-hour. This means that, in some respects, my relation to myself tomorrow is like a relation to another person. Suppose, for instance, that I have been worrying about some practical question. I now see the solution. Since it is clear what I should do, I form a firm intention. In the rest of my life, it would be enough to form this intention. But, when I am no this psychological branch-line, this is not enough. I shall not later remember what I have now decided, and I shall not wake up with the intention that I have now formed. I must therefore communicate with myself tomorrow as if I was communicating with someone else. I must write myself a letter, describing my decision, and my new intention. I must then place this letter where I am bound to notice it tomorrow. I do not in fact have any memories of making such a decision, and writing such a letter. But I did once find such a letter underneath my razor."