Evolution and science

Note: This is the 7th and last post in a series. Start at the beginning and read "up":
http://bartfusn.blogspot.com/2019/06/how-to-make-sense-of-it-all-theory-of.html

Daniel Kahneman, in "Thinking, Fast and Slow" describes two modes of thinking -- the fast, automatic, effortless kind, and the slow, halting kind that takes concentration and makes people tired.

It is the fast thinking that we share with other intelligent animals. The slow kind seems to be primarily if not exclusively a human invention. When we study in school, it is all about educating the slow-thinking side. One example is language. The spoken form is natural to all humans and learned by children without special instruction. It is part of fast thinking. Written language is an invention of the past few thousand years, and it does require special instruction and practice. Though to complicate matters, reading can become effortless and something we cannot turn off -- slow thinking turned to fast.

Starting in the 17th century, the slow-thinking sides of some gifted humans formed a community and launched the scientific worldview. It is all about answering "How?" instead of "Why?" Isaac Newton was a key figure. Some people scoffed at universal gravitation, thinking it ludicrous that things could affect each other without touching. His answer was that he had data and measurements on very different phenomena, and gravitation explained them all, and that trumped intuitive disbelief. He didn't know why gravity worked, but he knew how it worked. We still really have no idea why it exists.

That community of gifted humans in time grew to be today's impressive scientific establishment. Only a tiny fraction of humanity understands the intricacies of any particular point on the frontier of science, and perhaps it is only a small fraction that is gifted enough to understand it even if they decided to make it their life's goal. But the rest of us benefit from the discoveries and efforts of those tiny minorities. So we have jet planes, computers, and gene therapy.

Powerful telescopes tell us earth is a tiny speck in a sea of 250 billion other stars in our galaxy, and our galaxy is just one of 200 billion that we know of. At the other extreme, the microscopic scale, the world is just very strange, with particles popping in and out of existence and much happening based only on probabilities. Certain atomic-scale things cannot be measured without changing them.

At the intermediate scale, with regard to life, Darwin discovered and elaborated the theory of evolution by natural selection, and we know a great deal about how organisms work. Biochemistry has had a major role too.

Psychology is a case where slow thinking has come full circle to study the mind itself. It has discovered a great deal about how it works, including the instinctive, automatic fast thinking that is such a big part of who we are. A first approximation of how it differs from the clearer thinking of our slow thought processes is contained in a <list of cognitive biases>. And slow-thinking psychology has studied slow thinking itself.

However, our slow-thinking sides also have the ability to choose things that most people don't. We could choose to torture children, though thankfully hardly anyone does. We could choose to do things that are painful instead of pleasurable.

Someone could make it their life's goal to collect as many defunct microwave ovens as possible. They could make it their goal to chisel the letter "W" into as many rocks as their strength and longevity allowed. The range of what a few people will do in pursuit of their own private version of "art" is truly astonishing.

On the more positive side, we can choose to help strangers to the detriment of ourselves. We can value all humans equally without giving special preference to our nation, or our family. We can choose not to knowingly harm any animal.

Our slow-thinking side gives us the ability to defy generalizations science has made about how we will behave. But there is no objective reason anyone can give as to why those choices are preferable to the ones most people make. The closest we can come to making sense of life is to realize we are creatures shaped by evolution by natural selection.

This ends the series of posts on "the meaning of life".

(I wrote a blog post over ten years ago on how evolution explains why <happiness is transient>, which fits with this series of posts.)

Evolution and the arts

Evolution is on shaky ground in trying to say anything profound about music, dance, literature, theater, painting, sculpture and the like.

Most "primitive" cultures dance and sing and tell stories. One function of this may be to impress members of the opposite sex. Many other species have elaborate courtship displays. The exact form is essentially arbitrary, though they likely require physical attributes like strength, endurance, and fine motor control. By excelling at such a display, a potential mate shows good health and good genes. Dancing, singing and story-telling may serve that function among humans.

But why do we find some things beautiful and profound, others ugly or dull? Evolution shaped our cognitive machinery for adaptive purposes -- leaving more descendants. Scientists' best guess is that our sense of the beautiful and profound is a side effect of that cognitive machinery. It's a good guess that things most humans agree are beautiful or profound have those properties only through a human lens. Intelligent aliens arriving from another planet would be unlikely to find our arts very appealing since they would have evolved different nervous systems and cognitive abilities. One exception might be mathematical truths, as they are independent of the particulars of a given organism or environment. Prime numbers, golden ratios, and Fibonacci sequences might appeal to all intelligent beings.

Of course human culture is extraordinarily complex. Evolution can't come close to explaining anything but a tiny fraction of that complexity. But then -- neither can anything else. A belief in God certainly can't. It remains a mystery.

Evolution and religion

Humans have a strong tendency to believe in the supernatural. Some of what is "natural" is plain -- things that everyone can see, hear, or otherwise sense in essentially the same way. But beyond that, the distinction between natural and supernatural is very much a product of the accumulated wisdom of science. Universal gravitation is something we consider natural and real. But it is a form of spooky action at a distance, and not obviously more sensible than the idea that spirits live in trees and rocks.

We humans owe a lot of our success as a species to noticing relationships and regularities in the world and taking advantage of them. For instance, our band knows that root vegetables are a good source of food. Suppose we move to a new environment and find that the predominant root vegetable makes us sick. It is good if we suspect it too can be a good source of food if we can get past obstacles, and we experiment with different ways of cooking it or pounding it or treating it to see if any of them make the food edible. If certain prey animals show up in a certain place due to a particular combination of (say) season, recent rainfall, and the distribution of other predators, it is adaptive if we can detect that relationship. We are selected to try different things and keep doing the ones that work. However, this effort to find regularities is not highly developed -- we are not born with any refined intuitive sense of statistical significance, for instance. So we are also prone to finding false generalizations as well as true ones. The evolutionary approach would suggest that however imperfect we are at finding generalizations, the benefit of the true ones outweighs the downsides of the false ones.

"Primitive" humans trying to make sense out of the events of the world are dealing with not just other people but plants, animals, rocks, earth and sky. It is no surprise that they decide there are spirits in those things to try to explain what they otherwise cannot explain.

As for belief in one all-powerful God, this idea is appealing as a natural extension of childhood. As children we trust our parents to have everything figured out. If we explore the world as children and find confusion or danger, we can return to our parents and they will protect us. To a young child, parents seem all-knowing, all-powerful, and all-good. As adults our intellect may make us wonder about why we're alive and why we should follow society's rules. We may find ourselves overwhelmed trying to think everything through. A God who is very much as we viewed our parents is a comforting salve for a mind thinking things through too much. The idea of a reward for being good little boys and girls also fits in nicely with adults being good and doing what they think God wants them to do.

Along with religion comes the hope for an afterlife. This makes our mortality more bearable and is adaptive for that reason -- in some cases it may be a deterrent to suicide. As it happens, in successful religions a good afterlife is dependent on doing certain things -- almost always ones that in fact improve our fitness. It is a very unusual religion that discourages everyone from having any children, and we know what the fate of the Shakers was. No religion suggests cheating members of our own social group or neglecting children. Our brains may be wired to support belief in supernatural entities which enjoin us to do things which in fact increase our fitness in the natural world where we leave more or fewer descendants.

Evolution and morality

Objective morality may not exist, but morality does exist as a feature of human cultures and the human minds that underlie them. Scientists have documented reciprocity as a human universal that benefits everyone. Let's scratch each other's backs, but if you don't scratch mine after I've scratched yours, I'll notice and punish you for it. We humans aren't generally so good at solving logical puzzles, but if you find one that can be framed as a "cheating detection" problem, we're very good at it. Mutual aid helps us survive and reproduce, and refusing to aid others if they don't aid us keeps them from taking unfair advantage of us.

Humans are wired to identify with a group, belong to the group, and care passionately for its success independent of their own individual success. This started out as adaptive for the hunter-gatherer band, but has extended to larger units of organization as well. The ease and passion with which we modern humans can care deeply for the success of the local sports franchises shows how strong a tendency this is in us. It's not that people are willing to sacrifice all their personal interests for the group (think of the failure of collective agriculture most places it has been tried), but they will invest something in the group.

A popular position of moral philosophers is consequentialism or utilitarianism, whereby we should seek the greatest good for the greatest number. This would suggest that people in rich countries should give almost all of their resources to improving the lot of people in poor countries. But in fact, this very rarely happens. Humans tend not to share with people who are "other". Not many people give money to people far away. The nation-state is a very important unit of organization in today's world, and indeed Americans will often give to charities specific to America. But we're even more likely to give to our own community -- and most likely of all to save the bulk of what we have for our families. This suggests that morality as practiced by real people is more in line with evolution than abstract philosophical considerations.

Another prominent moral philosopher was Kant. His key insight was the categorical imperative, "Act only according to that maxim whereby you can, at the same time, will that it should become a universal law." I think one implication of that would be that in (say) 1980, when you could predict that the sum total of carbon emissions had a significant chance of making the earth a much worse place, each citizen of the earth would be obligated to reduce our carbon emissions to a level whereby we would have avoided this scenario. Obviously this didn't happen. It's hard to think of any cases where large numbers of people have followed this rule when it was counter to their own selfish interest. Once again, morality as actually practiced was shaped by evolution and is mostly impervious to philosophical argument.

Evolution, survival, and suicide

We humans are aware of certain things that other animals don't seem to be aware of. We know we will die. When we focus intently on that fact, we find it very unpleasant. Existential angst may not be adaptive, but thinking creatively about ways to postpone death has a clear adaptive purpose -- living for another day is another chance to reproduce or help your offspring to thrive. And while humans do sometimes commit suicide, it is rare. Existential angst is sufficiently controlled that most of us live as long as we can, even when suffering pain and despair. Why? There's no objective, logical reason, but it surely looks like an adaptive aspect of our minds molded by evolution. Genes that predisposed a significant portion of people to kill themselves would be selected against by evolution.

This is as good a time as any to counter objections along the lines of, "If we are molded by evolution, why do some people commit suicide? Why is there homosexuality? Why do some people kill their children?" Fundamental to evolution is the idea of variability -- different genes result in different consequences. This variability is a necessary condition for evolution to take place. If all members of a species were perfectly adapted to some environment and their genes were identical, then when the environment changes there would be no basis for adapting to the new one. The animal lineages that have survived have some variability, much of it not helpful for the current environment. As a result, at any given time there are traits that are not adaptive -- but they are present only in a very small part of the population. All the human genetic diseases fall in this category of variability. What they all have in common is that they are rare. Natural selection keeps trimming them back and keeping the frequency of the causal genes low. But if the environment changes, one of these genes that is now not adaptive may suddenly become adaptive, may dramatically increase in the gene pool, and help humanity adapt to this new environment. Suicide, homosexuality, and killing of children are all very rare, and as such are not arguments against evolution.

So we mostly work very hard to postpone death as long as possible. And yet there are exceptions to this -- ones that prove the rule. Women and men will both sometimes risk death in defense of their children. We all die and our genes survive only through our children, so sometimes it is more adaptive to die ourselves if we can save the lives of our children.

Men also have a willingness to band together into military units to fight other bands of men, with a significant risk of death. But in our environment of evolutionary adaptation (EEA), defeating a neighboring band was often accompanied by stealing or raping their women, providing more opportunities to leave descendants, and this may have offset the risk of death. Even today, with men organized into armies instead of bands, the rape of conquered women is all too common.

One classic dystopian future involves the computers achieving sentience and then taking over the world and exterminating humanity. To me this seems incredibly unlikely, because there is no inherent reason why an artificial mind should want to preserve itself or replicate itself. From the very beginning, evolution has selected above all for survival and reproduction in organisms. As consciousness developed, those same pressures made the overriding goal of that consciousness to survive and leave descendants. Thinking that a sentient intelligence would naturally have those same goals seems to me like projection. Our minds care deeply about those things based on evolution, but no evolutionary process has operated on computer programs. We would have to program it to want to survive and replicate itself. We have to program it to "want" anything.

Evolution, care of the young, and sex versus reproduction

It's no surprise that we seek out sex and enjoy it. It's no surprise that women as female mammals are strongly motivated to care for their offspring. Unlike most mammals, humans have evolved so that adult males provide resources (originally this was mostly food) for the children they have fathered, so they also care about the welfare of those children and invest a great deal in them. That is exactly what evolution by natural selection would predict.

Our desire for our children to thrive, and our willingness to invest heavily in them is so commonplace that we may lose track of how it's not obvious. Even selfish people who treat those outside their families very poorly most often leave all their assets to their children. We don't say, "Oh, he wasn't selfish -- he left money to his children!" In our minds, leaving money to our children *is* a form of selfishness. Given that we are all mortal, this is exactly what evolution would predict. Even selfish people with considerable money rarely spend all they have on hedonistic pursuits in their later years, but instead think it is right to leave something to their kids. They will typically do this even when their children are estranged, or hate them, or have adopted values very different from the parents' own.

At the heart of evolution by natural selection is leaving many descendants, and where this starts is being the father or mother to many children. The advent of reliable contraception in the past 70-odd years has created a major divergence between current selection pressure and that operating at any time in the past. Evolution did not require us to actively want to have children. All it required was the desire to have sex. Sex naturally caused pregnancy and in turn babies were born. Evolution has shaped us so that once they are born, it is a very high priority to care for them. But evolution never made us say, "I would like to have children." I think all human societies understand that sex causes pregnancies, and people in earlier times may have had the idea that they had enough children already. But this competed with the immediate urgent desire to have sex, and also a male's insistence on having sex with his mate even if she didn't want to. These factors are still in play in the large parts of the world that do not have access to reliable contraception.

But where contraception (and as a fallback, abortion) is freely available, birth rates have plummeted. We can fulfill our urges to have sex without having children. Of course many people do want children, but they typically want just one or two. Evolution's goal is to have many children. While medical advances have cut child mortality dramatically, three is still a minimum for a population to replace itself where a significant number of people choose to have no children at all. Why do people not want lots of children? For those of us who are fairly well off, there are opportunity costs -- lots of fun things we could do with our time instead of raising children. Also, we care about the welfare of our children, and realize that our existing one or two children will thrive better if they do not have to share our limited resources with further children.

The resulting dynamic seems to be that people in rich countries do not replace their numbers, but their place is taken by immigrants from regions where reliable contraception is not available. When those immigrants take on the values of the rich societies and have access to contraception, then they do not replace themselves either. But there are always more immigrants to come in, creating perhaps a dynamic equilibrium.

If this state of affairs persisted for thousands of years, evolution would strongly favor genes that tend to make people want to have a lot of children, not just a lot of sex.

Evolution would favor genes predisposing men and women to be willing to pay large sums to be sperm donors and egg donors. The fact that no such donors today pay for the privilege, and that egg donors in particular need to be paid for their services shows that evolution has made us want sex, but did not make us want to have offspring.

How to make sense of it all? The theory of evolution

I've joked sometimes that if I needed to come up with an epitaph for my gravestone, it might be, "I don't know." Yet of course, "not knowing" isn't a very satisfying answer. I'm reminded of the line from Paul Simon's song, disapproving of a person constantly saying "I have no opinion about that" by reframing it as, "I have no opinion about me."

There's a great deal that we don't know.  "How did wings develop on animals?" or "Why are there so many galaxies and stars?" Science is working on those, but most of us don't lose sleep over them. The questions that we all seem to care about a lot more are, "Why are we here? What gives life meaning? What should I do with my life?"

I've argued that there is <no objective morality>.  I've argued that <there is no God>. I'm not sure I need to argue that there is no objective "meaning of life" in the absence of objective morality or God, as I can't see what candidates there would be.

The best answer to, "What should I do with my life?" is to pick something, decide that it's what's important, make it your own, and work for it. In the absence of objective morality, there is no argument to be made as to why any choice you make would be fundamentally, profoundly right or wrong.

Yet when we look at what humans pick and what guides their choices, there is a great deal they have in common. So I offer answers to questions that are slightly less profound than "What is the meaning of life?", namely: "Why are our minds the way they are? Why do we want some things and want to avoid others? Why do we think some things are important or moral or 'right living' and others are not?"

This will take a while. I've divided it up into seven separate posts.

The best framework I know of for making sense of our lives and the world is evolution by natural selection. This is the foundation of all of modern biology, and one of the best-supported scientific theories there is.

You can look up <Evolution> so I won't go over the basics. But one critical concept I want to raise is the environment of evolutionary adaptation (EEA). We humans (and our hominid ancestors) evolved over the course of millions of years in hunter-gatherer bands. Only in the past few thousand years have we lived in larger units of political and economic organization, initially triggered by agriculture. That is not very much time for natural selection to change our minds. We may sometimes have traits that were adaptive in the EEA but are not adaptive today.

Our bodies evolved countless unconscious processes -- regulating temperature, water content, eliminating waste through kidneys, healing wounds with scabs, on and on. All the "lower" life forms have their own versions of solutions to such problems, and often our solution is the same as organisms quite different from us. These are the focus of the field of biology, but I focus below on our conscious experiences, since those are what concern us.

We are mammals, and we share with other mammals a great many things. We mammals feel pain when our bodies are damaged, and this unpleasant sensation motivates us to avoid such situations. We avoid being too hot or too cold. We enjoy food, and it's no surprise that we are motivated to find enough. Even people who have been hungry for a long time never really adapt to that circumstance -- they always want enough to eat. That is of course entirely consistent with surviving.

The exact relationship between conscious experience and the physical world is an unanswered puzzle and one which many thinkers (and I) see absolutely no prospect of answering. But whatever the relationship, it makes sense that our conscious experience shares the same goals of survival with our physical bodies. We know conscious experience depends on a physical body, and if your consciousness is in control of your actions and has no interest in eating, the body will die and with it the consciousness.