Global Warming

Keynes famously remarked that in the long run we are all dead. The recent volcanic activity in Iceland should help remind us why. A very powerful volcanic eruption would result in what has become to be known as a "nuclear winter;" that is, the earth would be covered by a cloud of dust so thick that it would cause massive drops in temperature and end most life (some bacteria can survive almost anything), which is also what would happen in the event of a nuclear war. An asteroid collison could do the same thing.

However, eventually the molten core of the earth will cool down, eliminating volcanoes, but putting earth into a deep freeze. The glacier that once covered New York City was twice as tall as the Empire State Building. The entire earth will be covered in extreme cold. Goodbye humans.

Now it seems entirely correct that global warming has been occurring over the last 300 years and it is most likely due to carbon emissions and the destruction of forests so that people can farm (causing a shortage of carbon-dioxide-eating life). In the relatively short run this is going to cause some problems, such as to make my friends' beachfront property uninhabitable.

It is interesting that humans have become a species-loving life form. For most of their short history, most humans never traveled more than a few miles from home and didn't really care what happened to other humans. At some point in the recent past, humans starting forming their identities around being a member of a nation group...really a much bigger tribe. And then within the national identity, shortly after becoming a nation, Americans became followers of political parties. So identifying with a species is really quite a step. And some people can even identify with other life forms. But 99% of every species that has ever existed has become extinct. And we will get there, probably long before the lava cools down. Carpe diem. It may not be around tomorrow.

Addendum: This post should be read while playing The Humans Are Dead by Flight of the Conchords.

The Ancestor's Tale

I recently finished Richard Dawkins’ The Ancestor's Tale. It is a readable opus on evolution back to the beginning of life. It looks at history backward; each species came from a certain past but there was no inevitability that any species would survive. Evolution is a story of who has survived and there were many possible ways the world could have been. The advantage of looking backward is that we can avoid the temptation to attribute to our ancestors any drive to progress or other teleological mechanism which suggests our destiny.

All apes share an geneological ancestor (concestor) who lived about 18 million years ago (18,000,000). All known life forms can be traced to a single ancestor (concestor) who lived more than 3 billion years ago (3,000,000,000). The continents were still joined together 150 million years ago. Human agriculture began about 10,000 years ago and human civilization (the Sumerians) about 7,000 years ago. I write the actual numbers because it is so hard for us to conceive geological time in its vastness. Tasmanian aboriginals, a form of homo sapien, were isolated from Australia about 13,000 years ago on the island of Tasmania, when land bridges were flooded by rising sea levels. This was the most recent isolation that lasted to modern times. They were discovered in about 1800 A.D., and exterminated by 1876 by agricultural settlers who viewed them as vermin.

What is the most recent common ancestor (MRCA) of all surviving humans today? It is quite clear that if we go sufficiently far back, everybody’s ancestors are shared. This makes geneology seem to me to be a bit parochial, although I have gotten sucked into the process at various times. Unfortunately, most of our family tree will remain unknown, so we need to estimate this by use of mathematics.

Assuming that population size is kept constant and mating is random, the surprising answer is only 12.3 generations ago. Assuming four generations per century, this is less than four centuries ago. It is even less if people reproduce younger than 25, which they probably did.

You can trace male genetic evolution through the Y chromosome and female genetic evolution through mitochondrial DNA. Once the last Tasmanian died, the most recent common ancestor of all of us alive today instantly jumped forward 10,000 years. By traveling up the tree father to father, the common male to all of us (Adam) dates back about 60,000 years while doing so mother-to-mother the common female (Eve) dates back 140,000 years. How can this be?

And here is another stunner: for particular genes, you are more closely related to some chimpanzees than to some humans.

Much of human knowledge defies “common sense,” or “conventional wisdom.” And I think these facts show that many of our moral or political stereotypes are based on very unscientific thinking. How can one claim a large division between races? Between religions? Between national identities? Between ourselves and other living creatures? It seems like you need to rely on some sort of creationism that marks humans or some kind of humans as a separate kind of thing. This is belied by DNA research and the fossil record. We share 98% of our DNA with chimpanzees. Get over it! You aren't that special.

That is just from the first 40 pages. Things get stranger and more interesting the further back you go.

The Selfish Gene and Altruism

I just finished Matt Ridley's book The Origins of Virtue. It was a great pleasure to read because it consistently managed to stand particular ideas of mine on their heads. Ridley persuasively argues that humans have social instincts, ultimately to be trustworthy. Virtuous behavior has been selected for by our genes.

The Selfish Gene is, of course, a famous book by Richard Dawkins (which I have not read) about a revolution in biology. At its core, the idea is that "individuals do not consistently do things for the good of their group, or their families, or even themselves. They consistently do things that benefit their genes because they are all inevitablly descended from those that did the same. None of your ancestors died celibate."

This conception solved some mysteries in biology. Social insects who help their sisters to breed rather than trying to breed themselves, left more copies of their genes in the next generation. "From the gene's point of view, therefore, the astonishing altruism of the worker ant was purely, unambiguously selfish." But how does that leave space for altruism?

Classical economists had supposed that people act out of self-interest. However, this idea revealed a much more powerful engine of behavior. "Selfish genes sometimes use selfless individuals to achieve their ends. Suddenly, therefore, altruism by individuals can be understood." People really do act selflessly because this tendency is selfishly useful for their genes.

What makes human beings different is culture, which leads to a different kind of evolution; a competition not just between genes, but between culturally different individuals or groups. "A person may thrive at the expense of another not because he has better genes, but because he knows or believes something of practical value."

There is one kind of cultural learning that makes cooperation more likely: conformism. It must be remembered that we evolved as small groups of hunter/gatherers, so conformisn strengthened the group. Thus, we get the tendency that it is usually cheaper and better to do what other people say. Humans have always fragmented into hostile and competitive tribes. This leads to our tendency to perceive the world in terms of us or them (the competing group). And war. This is the dark side of our social instincts.

The book also makes use of game theory; in particular, strategies for dealing with prisoner's dilemmas, a difficulty that occurs whenever there is a conflict between self-interest and the common good. This is a situation where each indidividual in a group will rationally choose a course of action that is not really in his own self-interest, another mind-boggling concept.

The book is full of wonderful anthropological studies, including many hunter/gatherer societies we have encountered in the modern age, and comparative biology between species. Once again, I am forced to realize how little I know, but that just means that there are more interesting surprises in store. On to Genome.

Overconfidence

In my last post, I raised the question why most people seem unwarrantly confident in their own opinions. I suggested that this may be partly due to fear. But there is another reason. Because it is naturally how we, as human beings, think.

The groundwork for modern behavioral economics was laid by Kahneman and Tversky. In the old model of human rationality, it was assumed that people were able to make probablistic calculations. What has been found is that instead we use unconscious rules of thumb, or "heuristics." These thought processes probably had evolutionary value at some time. Better to think fast when the lion is coming than reason.

One of the heuristics is to generalize on the basis of insufficient evidence. Once people are convinced that a small sample is representative of reality, they place unwarranted faith in their ability to forecast the future. Of course, overconfidence is often a valuable trait in itself. Currently, it leads people in sales, law and leadership positions to often be more effective. There is no reason not to think that some such traits often had evolutionary value in primitive societies, too. In order to have evolutionary value, it just means that you were more likely to pass on your genes. Certainly, the lotharios were better able to do this than the slackers.

There are other heuristics that make us likely to be wrong or overconfident. The availability heuristic leads people to give more weight to dramatic events, even if they occur less frequently. People can get "anchored" by even random occurences. For instance, studies have shown that a person presented a certain number randomly prior to making a decision will influence his decision dramatically. And then there is "confirmation bias." We tend to look for facts that confirm our already held views, rather than facts that would disconfirm them.

Often procrastination and laziness play in. It is easier go with your "intuition," your belief based on unconscious heuristics, than it is to deliberate. The latter requires effort. These tendencies have been correlated with regions in the brain by neurologists. Deliberation fires up the frontal cortex. Unconscious processes, the limbic system, which are the site of emotions. So even though it may be natural to be overconfident, the awareness of how little you know may also fire up the limbic system, making people even less likely to evaluate their beliefs. And the less likely you are to consider that you may be wrong, or even that your view is a prejudice based on little evidence, may make you even more overconfident.