He begins by using game theory to show that the self-interest theory contradicts itself. The self-interest theory has been the implicitly dominant theory for millennia: be a "good" Christian or Muslim, as defined in the holy books, if you want to get to Paradise. People who believe in an afterlife don't need to choose: morality and self-interest coincide. Everybody else has a problem: morality and self-interest are not necessarily the same thing.

(All reviewers of this book conclude that, according to Parfit, we often hold moral views that are self-defeating, but no reviewer can mention one example other than the one that i summarized).

If you think the first part (of four) was confusing, you ain't seen anything yet. The second part is about time: Parfit argues that morality should somehow be based on the past and the future to some degree, for example "should i do something even if i already know that i will regret it later?" The premise is interesting and original: we often discuss the the differences in rationality and morality between different persons at the same time, but we ignore the fact that the same person holds different views and behaves inconsistently at different times. Since (as we understand better in the third part) Parfit believes that each of us is de facto a new person all the time, then each of us "is" different people. What applies to me versus you should also apply to today's me versus yesterday's me (who was a different person). One logical conclusion is that the same morality that aims at protecting one person from another person's actions should also protect a future me from the actions of today's me. The "future self" has its own moral rights. When you smoke a cigarette, you might condemn your future self to lung cancer, and that should be a crime as much as when you shoot another person. In both cases you are harming someone else.

The best part of the book is about identity and consciousness. His famous thought experiment asks what happens to a person who is destroyed by a scanner in London and rebuilt cell by cell in New York by a replicator that has received infinitely detailed information from the scanner about the state of each single cell, including all of the person's memories. Is the person still the same person? Or did the person die in London? What makes a person such a person: bodily or psychologically continuity? If a person's matter is replaced cell by cell with equivalent cells is the person still the same person? If a person's psychological state (memory, beliefs, emotions and everything) is replaced with an equivalent psychological state is the person still the same person? What if the original is not destroyed, and now there is a perfectly identical copy of yourself living in London? Are both you? The question eventually asks what is "a life": is it a continuum of bodily states, whereby one grows from a child to an adult, or is it a continuum of psychological states? Or both? Or none?

Parfit believes that teleportation is simply a way for the self to travel from New York to London: yes, you are the same person in London that you were in New York Parfit believes that the self "is" the brain state. As the brain state changes all the time, the self cannot be the same: there cannot be a permanent "self". "I" do not exist. What exists is a brain state that right now is "me". The next brain state will also be a self, distinct from the previous one. There is a chain of successive selves, each somehow linked through memory to the previous one. Each self is distinct from the previous ones and future ones. The "I" is a mere illusion. There is no person that all those selves share. Derek Parfit believes in a Buddhist-like set of potential "consciousnesses", each with its own flow of feelings, although at each time the one which dominates gives me the illusion of having only one consciousness and one identity.

It is interesting that he finds solace in this "reductionist" view. He says it makes him less afraid of that. I guess, in a sense, we're dead all the time, so the final death is just yet another death in a long endless series of deaths.

This is not just philosophy for the sake of philosophy: your morality depends on what you think "you" is. If you think of yourself as a continuous being, you reach some conclusions. If you think yourself as identical to your brain, and therefore dying and being born another person all the time, you reach different conclusions on what is right and what is wrong. Your rational and emotional behavior depend on that assumption.

In the last part Parfit analyzes how future generations should influence today's morality. If you assume a materialistic viewpoint, future generations are real, even before they are born, and they have rights. The most basic of all rights is the right to live. My actions may determine if two people will meet, mate and have a child. My actions determine whether that child will exist or not. Suddenly, the responsibility is colossal: i am responsible for the lives of potentially an infinite number of people: that child will make children who will make children who will make children who... and all of those people may or may not exist depending on my actions. Terrifying.

Parfit's logic is powerful. When we talk of benefits or damages caused to future generations, we tend to neglect the one thing that matters most: will a person be alive or not? An action of mine that is meant to provide a better world to "future generations" might cause a person to never be born. Someone else will be born and benefit from my actions of today, but the main benefit for this person would be to be alive. The other person would never be born, so that person would never benefit from my actions, in fact that person would never even exist because of my actions. Do i have to feel morally guilty that, because of my actions, i have erased someone from the list of people who will exist? Can it be considered a form of "murder"? Murder applies only to people who exist; but then why am i concerned about what will happen to future generations, i.e. to people who don't exist?

If we assume that life is always worth living, then being alive is what counts more than anything else. If my actions cause someone never to be born, i can hardly claim that my actions were "good" for that person.

These and many other thoughts are triggered by Parfit's simple overture: "Each of us might never have existed". It takes very little for someone to exist or not exist: if your parents had postponed sex by a few minutes, your father's sperma would have been slightly different and chances are that "you" would have never been born, and someone else (a different child) would have been born.

We are fully aware that our actions have effects on the society of the future, but we neglect the fact that "society" does not identify the individuals who will actually be there, and that's one of the consequences of our actions. I can act in order to create a cleaner and safer society, but the result of my actions (and of many many many other people) will indirectly be to determine which individuals will actually live in that society. The fact of existing or not existing seems a much more important fact than whether the streets are clean and safe.

Parfit makes the point that we are responsible for the consequence of our actions on distant people: the fact that they are far from us does not mean we can cause them harm, like make them disappear. But the kind of responsibility we have towards people who are distant in time is not clear. We tend to care for children and grandchildren, but who is really concerned about the fate of a grandgrandgrandgrand...grandchild who will live one thousand years from now?

In another thought experiment Parfit examines the case of a teenager who is told to abort her child because it would be bad for her, but she decides to have the child anyway. If she had accepted and postponed having children by a few years, she would have been able to provide her child a better future. But this would "not" have been the same child, it would have been another child. Should the child who was actually born feel bad that her mother had him instead of waiting for a few years to have another child? Most likely no. When people advise the teenager to wait a few years before having children in order to provide a better future to the children, they are not thinking about the children (the children that will never be born). Claiming that this is "good for the children" is illogical: the children will never be born, and the children who will be born are different children for whom there is no better or worse anyway (it's not like they could have been born years earlier, because those would have been the original children who were never born). Again: if your mother had postponed sex that night by just a few hours, you would not exist, someone else would exist in your place.

Our choices about the future are inevitably cruel. We need to decide who will exist and who won't. When we try to act as to create a better society, we are indirectly causing a chain of actions that will lead some people to be born and many other people never to be born. The decision is generally based on providing the best to whoever will be born. We make decisions that decide who will later live and then feel responsible towards the people who will later live.

In search of the perfect moral theory, Parfit begins debunking all sorts of common-sense theories. He finds contradictions in most of the beliefs that we hold dear. By the end of the book he admits his failure to find "the" ethical theory that would solve all contradictions and give us what we want, what our common sense wants, in an ethical theory. He only has general hints for such a theory. The first one is that it probably has to be more "impersonal": some of the most dangerous contradictions arise when we work in tandem with many other people.

Parfit does not spend much time exploring the obvious possibility that a self-consistent ethical theory might be impossible, that one cannot remove all contradictions from morality (just like Godel showed that Mathematics cannot prove all theorems).

However, he ends the book on a positive note: that the history of ethics might just be beginning, that humans might finally be converging towards a common idea of what is good and what is bad after the tragedies of World War II and the scare of the nuclear holocaust. The book was written before the 2001 terrorist attacks and the whole Islam versus the world issues that arose since then. On one hand globalization has certainly made most of the world very similar (the West, the Far East, India, Latin America and most of Africa now share roughly the same values). On the other hand Islam has emerged as a powerful ethical force that has dramatically different values (mostly anti-democratic, anti-capitalist, anti-atheistic and intolerant of other beliefs). Whether the world is converging on a common direction or diverging yet again like it did in the Cold War and many times before that remains to be seen.

Parfit's highly technical essays are considered a modern classic of moral philosophy by the practitioners.

TM, ®, Copyright © 2012 Piero Scaruffi