Derek Parfit

"the part of our moral theory... that covers how we affect future generations... is the most important part of our moral theory, since the next few centuries will be the most important in human history."

"Classical Utilitarians...would claim, as Sidgwick did, that the destruction of mankind would be by far the greatest of all conceivable crimes. The badness of this crime would lie in the vast reduction of the possible sum of happiness."

"To be a person, a being must be self-conscious, aware of its identity and its continued existence over time."

"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."

"We are paternalists when we make someone act in his own interests."

"Venetian Memories. Jane has agreed to have copied in her brain some of Paul’s memory-traces. After she recovers consciousness in the post-surgery room, she has a new set of vivid apparent memories. She seems to remember walking on the marble paving of a square, hearing the flapping of flying pigeons and the cries of gulls, and seeing light sparkling on green water. One apparent memory is very clear. She seems to remember looking across the water to an island, where a white Palladian church stood out brilliantly against a dark thundercloud."

"Strawson describes two kinds of philosophy, descriptive, and revisionary. Descriptive philosophy gives reasons for what we instinctively assume, and explains and justifies the unchanging central core in our beliefs about ourselves, and the world we inhabit. I have great respect for descriptive philosophy. But, by temperament, I am a revisionist. […] Philosophers should not only interpret our beliefs; when they are false, they should change them."

"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."

"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."

"Nagel once claimed that it is psychologically impossible to believe the Reductionist View. Buddha claimed that, though it is very hard, it is possible. I find Buddha’s claim to be true. After reviewing my arguments, I find that, at the reflective or intellectual level, though it is very hard to believe the Reductionist View, this is possible. My remaining doubts or fears seem to me irrational. Since I can believe this view, I assume that others can do so too. We can believe the truth about ourselves."

"On all plausible theories, everyone’s well-being consists at least in part in being happy, and avoiding suffering."

"It has been widely believed that there are such deep disagreements between Kantians, Contractualists, and Consequentialists. That, I have argued, is not true. These people are climbing the same mountain on different sides."

"What now matters most is that we rich people give up some of our luxuries, ceasing to overheat the Earth's atmosphere, and taking care of this planet in other ways, so that it continues to support intelligent life."

"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."

"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."

"When I consider the parts of the past of which I have some knowledge, I am inclined to believe that, in Utilitarian hedonistic terms, the past has been worth it, since the sum of happiness has been greater than the sum of suffering."

"We live during the hinge of history. Given the scientific and technological discoveries of the last two centuries, the world has never changed as fast. We shall soon have even greater powers to transform, not only our surroundings, but ourselves and our successors. If we act wisely in the next few centuries, humanity will survive its most dangerous and decisive period. Our descendants could, if necessary, go elsewhere, spreading through this galaxy."

"Schopenhauer makes two curiously inconsistent claims about the wretchedness of human existence. We can object, he claims, both that our lives are filled with suffering which makes them worse than nothing, and that time passes so swiftly that we shall soon be dead. These are like Woody Allen’s two complaints about his hotel: ‘The food is terrible, and they serve such small portions!’"

"If we believe that there are some irreducibly normative truths, we might be believing what we ought to believe. If there are such truths, one of these truths would be that we ought to believe that there are such truths. If instead we believe that there are no such truths, we could not be believing what we ought to believe. If there were no such truths, there would be nothing that we ought to believe."

"Naturalism and Non-Cognitivism are both...close to Nihilism. Normativity is either an illusion, or involves irreducibly normative facts."

"Why do we save the larger number? Because we do give equal weight to saving each. Each counts for one. That is why more count for more."

"I sometimes want to kick my car[.] Since I have this anger at material objects, which is manifestly irrational, it’s easier to me to think, when I get angry with people, that this is also irrational."

"Even if moral truths cannot affect people, they can still be truths."

"Normative concepts form a fundamental category-like, say, temporal or logical concepts. We should not expect to explain time, or logic, in non-temporal or non-logical terms. Similarly, normative truths are of a distinctive kind, which we should not expect to be like ordinary, empirical truths. Nor should we expect our knowledge of such truths, if we have ay, to be like our knowledge of the world around us."

"To think about reality we must use concepts, and certain truths about concepts may reveal, or reflect, truths about reality."

"Though everything is identical with itself, only I am me."

"Why shouldn’t I eat toothpaste? It’s a free world. Why shouldn’t I chew my toenails? i happen to have trodden in some honey. Why shouldn’t I prance across central park with delicate sideways leaps? I know what your answer will be: “it isn’t done”. But it’s no earthly use just saying it isn’t done. If there’s a reason why it isn’t done, give the reason—if there’s no reason, don’t attempt to stop me doing it. All other things being equal, the mere fact that something “isn’t done” is in itself an excellent reason for doing it."

"When some principle requires us to act in some way, this principle’s acceptability cannot depend on whether such acts are often possible. We cannot defend some principle by claiming that, in the world as it is, there is no danger that too many people will act in the way that this principle requires."

"It’s a good reason for postponing pleasures that you will then have more time in which you can enjoy looking forward to them. I remember exactly when, at the age of eight, I changed over from eating the best bits first to eating them last."

"Consider the fact that, in a few years, I shall be dead. This fact can seem depressing. But the reality is only this. After a certain time, none of the thoughts and experiences that occur will be directly causally related to this brain, or be connected in certain ways to these present experiences. That is all this fact involves. And, in that description, my death seems to disappear."

"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."

"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."