Two Meanings of Life
A first meaning
Robin Hanson remarks on the relationship between evolution and values:
Biological evolution selects roughly for creatures that do whatever it takes to have more descendants in the long run. When such creatures have brains, those brains are selected for having supporting habits. And to the extent that such brains can be described as having beliefs and values that combine into actions via expected utility theory, then these beliefs and values should be ones which are roughly behaviorally-equivalent to the package of having accurate beliefs, and having values to produce many descendants (relative to rivals). Equivalent at least within the actual environments in which those creatures were selected.
Humans have unusually general brains, with which we can think unusually abstractly about our beliefs and values. But so far, we haven’t actually abstracted our values very far. We instead have a big mess of opaque habits and desires that implicitly define our values for us, in ways that we poorly understand. Even though what evolution has been selecting for in us can in fact be described concisely and effectively in an abstract way.
Which leads to one of the most disturbing theoretical predictions I know: with sufficient further evolution, our descendants are likely to directly and abstractly know that they simply value more descendants. In diverse and varying environments, such a simpler more abstract representation seems likely to be more effective at helping them figure out which actions would best achieve that value. And while I’ve personally long gotten used to the idea that our distant descendants will be weird, to (the admittedly few) others who care about the distant future, this vision must seem pretty disturbing.
This suggests an initial answer to our question. The meaning of life, understood as “the purpose of life,” is having many descendants.
Objections will be raised. In the first place, Robin is only arguing that in the distant future human descendants will have values like this. Why should it apply already? The problem with attempting to make this distinction is that it is merely a question of how conscious and explicit the purpose is. As I said here, purpose in evolved nature is real, and it does not have to be explicitly considered in order to be real. But the behavior in question is already present in humanity, and furthermore, it could not have possibly failed to be present without quickly leading to human extinction. And Robin says the same thing in his post; it is a question of how humans describe and think about their values, not whether they have these values. They certainly have them.
In any case, this motive is hardly hidden from people, even if it might become clearer in the distant future. Most people consciously want to have children, and most parents consciously want to have grandchildren. The Old Testament, written by people with biology and psychology no different from ours (in any important way relative to the time scale considered by Robin’s post) explicitly adopts the point of view that Robin attributes to future humans. For one of many examples, “I will make your descendants as numerous as the stars in the sky and will give them all these lands, and through your offspring all nations on earth will be blessed.” Again and again the Bible uses “descendants” as a description of the ultimate blessing. It is an extremely weak objection to point to the fact that people frequently use contraception as an argument that people are not interested in having descendants. People may want to avoid having a child at some specific point in time, but that hardly means (in the typical case) that they do not see having descendants as desirable. A bit of truth in this objection, however, is that we can expect future people to have less inclination to use contraception than current ones. This is likely even on relatively short timescales like a century or so, even if the main causes on this scale would have to be cultural rather than biological.
A second objection will be raised. This purpose or meaning is “ugly,” to put it in Robin’s terms. And in particular, it is not even coherent. The purpose of life cannot be to create more life; that would be circular, and consequently unintelligible as a purpose. Samuel Flieschacker, in The Good and the Good Book, makes an argument along these lines, although more specifically directed against the view that the purpose of life is to benefit others:
It sounds noble when someone says that we’re put on earth to help others, or to make the world a better place. But can that really be enough to make a life worth living? Helping others usually means making sure that they have adequate food and shelter, protection against violence, and a job that allows them self-respect—that they have all the conditions under which one can live a free and pleasant life. But once one has all these things, one still has to worry about what to do with them. Suppose everybody had all these things; suppose that injustice, violence, and poverty no longer existed, and most of us were able to avoid grave disease and natural disaster. What then? Would the question about the worth of life not arise even more acutely? In the midst of urgent threats to life and liberty, we can set that question aside; once the urgency has passed, it comes roaring back. Saying that we are here to alleviate the suffering of others just pushes the question off for a while. In a wonderful Peanuts strip, one character says to another that we are put on earth to help others, only to be asked, “what are the others here for?”
(Chapter 3)
The same argument could be made against the purpose of having descendants. If this is the meaning of life, what is the meaning of the descendants’ lives? If it is just “having more descendants,” this leads to an infinite sequence of “purposes”, which eliminates causality and therefore purpose as well.
Note that this reply does not prove the scenario cannot exist, but makes a claim about how we should describe that scenario if it existed. If the only “purpose” is having descendants, then we cannot truly speak about purpose in this context at all, and it would be more correct to say, “Life does not have any purpose. It is just something that happens.”
A second meaning
This is perhaps why Robin Hanson finds his vision of the future “pretty disturbing.” If future humans will value only more future humans, and nothing else, this is not a description of a future filled with meaning, but one truly meaningless.
However, while Robin’s description of the future is more or less correct, he is missing an important aspect of it here. It is true that evolution adapts creatures to the purpose of having many descendants. But the things that it produces in order to accomplish this have their own internal “meanings”, and these meanings cannot be eliminated without eliminating the things themselves, and therefore without preventing the descendants from coming into being.
In particular, the difference between humans and other animals, and the difference Robin is specifically considering in his post, is human intelligence. A creature without intelligence could not consciously consider its goals at all, and therefore could not describe those goals as including descendants. This implies the existence of an internal “meaning” or “purpose” which includes using this intelligence in order to understand one’s life and the world. This is Aristotle’s approach to the question of the meaning of life and to the nature of happiness.
Aristotle, as quoted in the above posts, speaks about various kinds of virtues and human activities. But let us try to be a bit more precise about this. Consider this passage (from Aristotle in the last linked post):
But such a life would be too high for man; for it is not in so far as he is man that he will live so, but in so far as something divine is present in him; and by so much as this is superior to our composite nature is its activity superior to that which is the exercise of the other kind of virtue. If reason is divine, then, in comparison with man, the life according to it is divine in comparison with human life.
We do not, according to this, have to get involved in complicated explanations of the details of human life in order to determine the purpose which arises “in so far as something divine is present” in us. The purpose is just using reason, which is to say understanding things. Humans have this purpose, and evolution cannot remove it from them without removing reason from them, and therefore without removing from them the very concept of purpose.
The meaning of life, then, is to understand reality, and to use reproduction to preserve the existence of a species that does this.
Criticism
This does not solve all my problems forever. Of course it does not. There is no question that requires such an answer, and no answer that would accomplish that goal. But I put this objection and response here because I think it is underlying factor that will continue to produce more objections and which basically explains Hanson’s question about the lack of obvious agreement on the meaning of life.
This does not even provide a basic sense of meaning. The objection would be that even if answering the question about the meaning of life does not solve all of a person’s problems forever, it should at least give them a basic feeling that their life is meaningful, and it is not clear that this answer will do that.
This is somewhat different from the previous case. There is no answer that will solve everything forever. But some statements about the meaning of life do give people a feeling of meaning and some do not, but this very much depends on context. In particular situations, some statements will give them such a feeling, and others will not. There is no reason to expect this in a general way from an abstract description of the human situation such as the one in this post. In other words, this again is basically an objection of the form, “this does not do for me what I expected the answer to do.” It is not an argument that the answer is not correct.
So you’re saying people without children have meaningless lives? Not at all, although it is a very obvious fact that people without children lack the above mentioned “feeling” of meaning much more often than people with children.
If you agree with Aristotle about the “divine” part of us, which I do, then most of the meaning of life does not come from having children. Nonetheless there will always be a tension between this “internal” meaning of the power of reason and the evolutionary reasons we have this power at all. Consider Aristotle’s (perhaps hyperbolic) remark, “Without friends no one would choose to live, though he had all other goods.” If understanding things is as good as I say it is, why do people feel the need to share it with others in order for it to be a meaningful experience?
We might remember Alexander Pruss’s remarks about intelligent sharks. If rational animals had evolved in a less social environment, we might feel less need for friendship. And if we had evolved using asexual reproduction living “hermit” like lives, we might feel no need for friendship at all. And yet both goals of “producing descendants” and “understanding reality” would remain.
The question “what is the meaning of life” and “what makes a person feel that their life is meaningful” are two different questions, and technically I have answered only the first question in this post, not the second.