Chapter 9                               The Practical Criticism of Bayesianism

 

In the first place, say its critics, Bayesianism simply can’t be an accurate model of how humans think because humans violate the Bayesian model every day. Every day, we commit acts that are at odds with what both reasoning and experience have shown is rational. Some nations still execute murderers. Some men continue to bully and exploit women. Some adults still spank children. Too many of us still fear people who look different from us on no other grounds than that they look different from us. We shun them even when we have evidence showing there are many trustworthy individuals in that other group and many untrustworthy ones in the group of people who associate with us. We do these things even when experimental evidence and everyday experience both indicate such behaviors are counterproductive. That is the opposite of Bayesianism.

Over and over, we act in ways that are illogical by Bayesian standards. We too often stake the best of our human and material resources on ways of behaving that both reasoning and evidence say do not work. Can Bayesianism account for these glaring bits of evidence that are inconsistent with its model of thinking?

The answer to this critique is disturbing. The problem is not that the Bayesian model doesn’t work as an explanation of human thinking and behavior. The problem is rather that the Bayesian model of human thinking and behavior works too well. The irrational, un-Bayesian behaviors individuals engage in are not proof of Bayesianism’s inadequacy, but rather parts of a larger proof of how it applies to the thinking, learning, behavior, and evolution not just of individual humans, but of whole communities and even whole tribes and nations.

Societies continually evolve and change because every society contains at least a few people who are naturally curious. Curious people constantly imagine and test new ideas and new ways of doing things like working, getting food, raising kids, fighting off invaders, healing the sick – any of the things the society must do in order to carry on. Often, subgroups in society view any new concept or way of doing things as threatening to their most deeply held beliefs. However, if adherents of the new idea keep demonstrating that their idea works better – gets more work done, saves more lives, nurtures better-adjusted infants into citizens, etc. – than does currently common practice, then the larger society usually marginalizes the less effectual citizens and their ideas and adopts the new way of farming, building shelters, healing the sick, etc.

In this way, a society mirrors what an individual does when he finds a better way of growing corn or teaching kids or easing Grampa’s arthritic pain. In this way, we adapt – as individuals, but more profoundly, as societies – to changes in our environments, and to new lands and markets and new technologies such as plows, vaccinations, cars, televisions, computers, and so on. Farmers, carpenters, teachers, doctors, etc. who cling to obsolete ways are passed by, often even by their own children or grandchildren.

But then there are the more disturbing cases, the ones that caused me to write in my last chapter that we are almost completely devoid of any unshakable beliefs. Sometimes large minorities or even majorities of citizens do hang on to obsolete concepts and ways, in spite of mounds of evidence which say those ideas don’t work as well in current circumstances as the new ones others are using.

The Bayesian model of human thinking works well, most of the time, to explain how individuals form and evolve their basic idea systems. Most of the time, the model also can explain how a whole community, tribe, or nation can grow and change its sets of beliefs, customs, and practices. But can it account for the times when majorities in a society do not embrace a new, more effective model, in spite of Bayesian observations and calculations showing the idea is sound and useful? In short, can the Bayesian model explain the biases that we see in the dark side of reactionary tribalism, the kind of thinking that works to return a society to the beliefs and customs of its past?

          Nazi party rally, 1934. Tribalism at its worst (credit: Wikimedia Commons)

As we saw in our last chapter, for the most part, individuals become willing to drop a set of ideas that seems to be losing its effectiveness when they encounter a new set of ideas that looks more promising. They embrace the new ideas that perform well, that more effectively guide the individual, the family, even their whole society, through the challenges and hazards of surviving in the physical world.

At the tribal level, whole societies usually drop models of reality, and the ways of thinking and living based on those models, when citizens repeatedly see that a set of new ideas is getting better results. When your neighbors are producing bigger crops, you want to know how and why, and you want to use the new practices that work. When the plague comes, you’ll do whatever works to keep yourself and your loved ones from getting it.

Sometimes, on the level of social change, this mechanism can cause societies to marginalize or ostracize subcultures that refuse to let go of the old ways. Cars and "car people" marginalized the horse culture within a generation. Assembly line factories brought the unit cost of goods down until millions who had once thought that they would never have a car, an icebox, or a TV bought one on credit and took it home. When assembly line factories came in, old, small-scale shops where teams of men made cars one at a time were obsolete.

The point is that when a new subculture with new beliefs and ways keeps getting good results, and the old subculture keeps proving less effectual by comparison, the majority usually do make the switch to the new way – of chipping flint, growing corn, spearing fish, making arrows, weaving cloth, building ships, forging gun barrels, dispersing capital to the enterprises with the best growth potential, or connecting a computer to the worldwide net.

It is also important to note here that, for most new practices, tests applied to them only confirm that the old way is still better. Most new ideas are tested and found to be less effective than the established ones. Only rarely does a more effective one come along. But the crucial insight into why humans sometimes do very un-Bayesian things is the one that comes next.

Sometimes, if a new paradigm – i.e. the worldview that underlies a new practice – challenges a tribe’s core beliefs, Bayesian calculations about what a society will do next fail. Sometimes tribes continue to adhere to obsolete beliefs. The larger question here is whether the Bayesian model of human thinking, when taken up to the level of human social/cultural evolution, can account for these apparently un-Bayesian choices and actions on the parts of individuals and their tribes.

Our most deeply held beliefs are those that guide our interactions with other people – family, friends, neighbors, colleagues, fellow citizens, and foreigners. These are the parts of our lives that we usually see as being guided not by reason, but by deep moral beliefs – beliefs grounded in sources much more profound than our beliefs about the sensory world. In anthropological terms, these are the beliefs that enable the members of the tribe to achieve social solidarity – to live together, interact, achieve teamwork, and get along as a tribal team.

The continued exploitation of women and execution of murderers described above are both irrational, but are both consequences of the fact that, in spite of our worries about the failures of our moral code in the last hundred years, much of that code lingers on. In many aspects of our lives, we are still drifting with our traditional ways, even though our confidence in those ways is eroding steadily. We don’t know what else to do. In the meantime, these traditional ways are so deeply ingrained and familiar as to seem to us to be “natural”, in spite of mounds of evidence showing that they are counterproductive.

When we study the deepest and most profound of these “traditional” beliefs, we are dealing with those beliefs that are most powerfully programmed into every growing child by nearly all of his tribe’s adult members. These beliefs don’t obey the Bayesian models that usually govern the learning processes of the individual. In fact, they’re almost always viewed by the individual as being the most crucial parts of his tribe and himself. They are guarded in the mind by programmed emotions of fear and anger. We get scared and mad when we think our values are being threatened. They are the beliefs that our parents, teachers, storytellers, and leaders enjoin us to hang on to at all costs. In fact, for most people in most societies, these beliefs and the morés that grow from them are considered “normal”. Varying from them is viewed as “abnormal”.

For centuries, in the West our moral meta-belief – that is to say, our belief about our moral beliefs – was that they had been set down by God and, thus, were universal and eternal. When we took that view, we were in effect placing our moral beliefs in a separate category from the rest, a category meant to guarantee their immutability. Non-Western societies do parallel things. 

 

 

     

                                  

                                  John Stuart Mill (credit: Wikimedia Commons)

 

But are our moral beliefs really different from our beliefs in areas like Science, athletics, farming, cooking, or automotive mechanics? 

The answer is “yes and no”. We are eager to learn better farming practices and medical therapies, and to win at track meets. But, in their attitudes about the executing of our worst criminals or the exploitation of women, many in our society are slow to change. Historical evidence shows societies can change in these areas, but only grudgingly. (J.S. Mill, a nineteenth-century British philosopher, discussed the obstinacy of old ways of thinking about women, for example, in the introduction to his essay, The Subjection of Women.¹)

So, can these core beliefs – our values – still be understood in a Bayesian way? Yes. But in a very harsh way. Sometimes, the moral beliefs that humans hold most deeply only get changed in an entire nation when experience proves by pain that the old values no longer work, i.e. when the values begin to fail as guidelines by which the humans who hold them can effectively make choices, act, and live their lives. In extreme cases, values fail so totally that the people who hold old values begin to die out. They starve or become ill or fail to reproduce or fail to program their values into their young. Or the whole tribe may even get overrun. By one of these mechanisms, a tribe’s entire culture can die out. The tribe’s genes go on in children born from the merging of two tribes, but most of the losing tribe’s culture becomes a footnote in history.

And so it is that, as the critics of Bayesianism point out, humans of past societies often behaved in ways that seem irrational by Bayesian standards. (One of the main aims of this book is to try to provide a way of thinking that makes deep change doable and in fact so readily doable that a society can change its values without thousands, or even millions, of its people getting killed.)

Even in our time, some adults still spank kids. Some men still bully women. Some states still execute murderers. Research on these morés says they don’t work; these behaviors do not achieve the results they aim for. In fact, these patterns of behavior and the beliefs underlying them exactly fit the term counterproductive. States that execute killers have higher murder rates.

Why do we sometimes act irrationally? Because our culture’s institutions – the family, the schools, and the media – continue to indoctrinate us with these values so deeply that once we are adults, we refuse to examine them. Instead, our cultural programming causes us to bristle, and then to defend our “good old ways”. Violently if need be. If the ensuing lessons are harsh enough, and there is a reasonable amount of time available, a society can sometimes learn, change, and adapt. But deep social change is difficult. Alfred Whitehead, in 1927, wrote: “The major advances in civilization are processes which all but wreck the societies in which they occur”.^2.

  

             

                                Lethal injection room, used to execute criminals  

                                               (credit: Wikimedia Commons)                           

                    

                           Alfred North Whitehead      (credit: goodreads.com) 

 

 

It is also worthwhile to say the obvious here, however politically incorrect it may be: all our obsolete-obstinate beliefs, values, and behavior patterns did serve useful ends at one time. That is why we acquired them in the first place. 

For example, in some early societies, women were taught to be submissive, first to their fathers and brothers, then their husbands. The majority of men in such societies were thus more likely to help to nurture the children of their socially sanctioned marriages because each man was confident the children born to “his” woman (or women) were biologically his.

Raising kids is hard work. It requires constant attention to reams of hazards. In early societies, if both parents were committed to the task, the odds were better that those children would grow up, marry, have kids of their own, and then program into those kids the values and roles that their parents had been raised to believe in. Non-patriarchal societies taught other roles for men and women and other designs for the family, but they weren’t as prolific as patriarchy over the long haul.

Patriarchy isn’t fair. But it makes lots of babies who become adult citizens. Workers. Soldiers. Lots of them. This view of patriarchy is harsh, but real.

Patriarchy’s beliefs about male and female roles didn’t work to make people happy. But they did give some tribes numbers and power. They are obsolete today, partly because child nurturing has been largely taken over by the state (public schools), partly because no society in a post-industrial, knowledge-driven economy can afford to stifle half its human resources (i.e. the female half), and partly because there are too many humans polluting the Earth now. 

Population growth is no longer a wise goal because it no longer brings a nation power. In today’s world, millions of poor are likely to be a liability, not an asset, for a nation. They don’t produce goods and services at anything like the rates of more skilled workers in developed societies. If they suffer too much, they might even start a violent revolution and unravel their own way of life, i.e. destroy the old order. 

 

   

              

         

                        Chapter 8.                     How Pervasive Is Bayesianism? 

                      Girls Learning Sign Language, a code for communicating  

                              (credit: David Fulmer via Wikimedia Commons) 

The idea behind Bayesianism is straightforward enough to be grasped by nearly all adults in all lands. But radical Bayesianism escapes us. The radical form of Bayesianism says all we do fits inside the Bayesian model. But it is very human to dread such a view of ourselves and then to slip into thinking Bayesianism must be wrong. We want desperately to believe that at least a few of our ideas are unshakable. Too often, unfortunately, people think they have found such an idea. But a true Bayesian knows that probably the only absolute truth is the one that says there are no absolute truths. In reality, even though we suspect that our familiar ideas and beliefs are not perfectly certain, we still use them to interpret, reason, and act in the world. Why? Because we have to. We have to move through the day. We can’t sit catatonic. We gamble that smart gambling is the best of our choices for ways to get through the decade and the day.

An idea is a mental tool that enables you to sort and respond to sensory experiences – single ones or whole categories of them. ("Balsamroot! Tasty.”) (“Poison ivy here. Stay away.") ("That’s a clip of Martin Luther King in Selma. That’s real courage.")

 

When you find an idea that enables quick, accurate sorting, you keep it. What can confuse and confound this whole picture is the way that, in the case of many of your most deeply held, deeply programmed ideas, you didn’t find them. They came by trial-and-error to some of your ancestors, who found the ideas so useful that they then did their best to program these ideas into their children. Then, the ideas were passed down the generations to you.

 

Many ideas you acquire are added to your mental toolkit after Bayesian analysis by the process of your own noticing, considering, and testing them. But you pick up many more ideas from your family and tribe. This cultural programming is being instilled in you because people of your tribe acquired, tested, and affirmed those ideas by the first process. Furthermore, those ideas worked. Your forbears survived well enough to pass those ideas down the generations to you partly because they had adopted and used those ideas.

 

Observe, hypothesize, test, adjust, test some more: these are the marks of Bayesianism, the model by which we grow and move forward, individually and as nations. And a Bayesian never concludes about any of his ideas that the idea is final.

 

Culture, consciousness, even sanity, are constantly evolving for all humans all the time. All of us keep updating our ideas/beliefs. This is true for ideas as complex as justice and love and as basic as up and down. (Individual minds can indeed be made to reprogram their notions of up and down.¹) And in this picture, “I” is a dynamic, self-referencing system that is constantly checking its perceptions of the evidence in reality against ideas, models, and concepts of what it believes reality should be, then updating itself.

 

Admittedly, a few very general ideas are not acquired by humans via either of the above methods of individual learning or social programming. They are hardwired into us by our genetic code. They don’t fit into either of the categories just described. But they fit inside the Bayesian model because they can be studied by scientists using Bayesian methods.

 

Some of the genes that cause a language center to develop in a fetus’ brain are still being located. The brain areas holding them also are only partly understood. But they’re being studied in physical reality (e.g. Broca’s area). They are not nebulous Rationalist concepts about concepts.  

 

In our present discussion, we can pass these innate concepts by. They are biological rather than philosophical – hardware rather than software – so they are outside of our present scope. These genes, and the brain structures that are built from the information coded into them, may even be manipulated one day, for a whole range of possible ends, by behavior modification, genetic engineering, drugs, surgery, or other technologies we today can’t imagine.

 

But for our purposes here, in our search for a universal code of moral values, Neurophysiology’s usefulness runs out. Whether techniques for manipulating the brain/mind will be judged right or wrong and whether they will be allowed in our society will still depend on values already programmed as “software” into future tribes of humans. Values like freedom and dignity. These values, as we have already seen, are going to need something more in the code at their core than what is offered by our current Science.

 

Empiricism, as a moral guide, has proved unreliable in theory and practice. In short, so far, Science has failed at being its own moral guide.

 

Even in Neurophysiology, knowing the structure of the brain cannot tell us how brains should be used. Bodies and brains are hardware; moral codes are software. How we should program hardware is not revealed by studying hardware. What ideas we should put into brains is not made clear by studying brains.  

 

Figuring out what we should be programming into human minds requires that we examine the fit between our software – including our moral codes – and reality, i.e. the world. Do our morals work? Do they lead us to live wiser, healthier lives and, most of all, to survive? In the end, that is the crucial test of any moral code. This thought returns us to our project of finding a foundation for some new core software – i.e. a new moral code – and so to Bayesianism. 

 

The Bayesian model of how we think is so radical that at first it eludes us. To each individual, the idea that he must continually adjust his entire mindset, and that no parts of it, not even the most deeply held ideas of who he is or how reality works, can ever be fully trusted, is disturbing to say the least. Doubting our most basic concepts is like flirting with mental illness. Even considering the possibility is upsetting. But this radical Bayesian view is certainly the one I arrive at when I look back honestly over the changes I have undergone in my own life. The Bayesian model of how a “self” is formed, and how it evolves as the organism ages, fits the set of memories that I call my “self” exactly.

 

Thomas Kuhn is the most famous of the philosophers who have examined the processes by which people adopt a new theory, model, or way of knowing. His works focus on how scientists adopt a new scientific model, but his conclusions can be applied to all thinking. His most famous book implies that all our ways of knowing, even our most cherished ones, are tentative.² Human knowledge grows and changes as humans advance, by paradigm shifts, from obsolete ideas to newer, more effective ones – i.e. by leaps, rather than in a steady march of gradually growing understanding. We “get” a new theory by a kind of experience that is like a religious conversion.

 

Thus, Kuhn confirms what Bayesianism tells us about our ways of growing our thinking: real growth is always surprising; it always moves into newer, better ways of thinking by a revolution inside our sets of beliefs. In this book, the moral code we are aiming to write for future generations of humans round the world is going to have to take this evolving nature of human culture into account. Our new code is going to have to provide for its own constant updating.

 

Caution and vigilance seem to be the only rational attitudes to take under such a view of the universe and the human place in it. To many people, the idea that all the mind’s routines, perhaps even the mind’s operating system – i.e. its sanity – are tentative and subject to constant revision seems absurd. 

But then again, cognitive dissonance theory leads us to predict that we would dismiss such a scary picture of ourselves. We don’t want to see ourselves as incapable of forming any unshakeable beliefs. But history and experience both show that we’re almost completely devoid of any unshakable concepts. (Why I say almost completely will become clear shortly.) 

 

Ultimately, our way of thinking, learning, and evolving in all matters is either Bayesian or doomed. On the tribal scale, tribes either evolve or die out. That’s a rule of living. In real existence, real survival, there is no other way.

 

At this point in the discussion, opponents of Bayesianism begin to marshal their forces. Critics give many reasons for disagreeing with Bayesianism. I will deal with the two most telling – one is practical and evidence-based, and the other is theoretical. We’ll disarm the evidence-based attack in the next chapter, the theoretical one in the chapter after that.

 

 

 

Notes

 

1. Jan Degenaar, “Through the Inverting Glass: First-Person Observations on Spatial Vision and Imagery”

Phenomenology and the Cognitive Sciences 12, No. 1 (March 2013).

 

2. Thomas Kuhn, The Structure of Scientific Revolutions (Chicago: University of Chicago Press, 3rd ed., 1996).

 

                                Chapter 7.                    (conclusion) 

Evolution for all species proceeds, mostly, by the combined processes of genetic variation and natural selection. It doesn’t matter how often the anatomies of already existing members of a species are altered if their gene pool doesn’t change. If the species’ gene pool doesn’t change, then the next generation will, at birth, basically look pretty much like their parents did at birth. Chopping off a dog’s tail doesn’t change the tail genes it carries in its sperm or egg cells.

Under Lamarckism, by contrast, an animal’s genes are pictured as changing because the animal’s body has been stressed in some way. Lamarckism says a chimp, for instance, will pass genes for larger arm muscles on to its young if the parent chimp is forced to use its arm muscles a lot.

But Darwinian evolution gives us what we now see as a far more useful picture. For example, in nature, if several plant species in an area are changing their appearance, individual within an animal species there that are no longer well camouflaged in the changing flora become easy prey for predators, and so they never survive long enough to have babies of their own. Or, in another example, ones that are unable to adapt to a cooling climate die young or reproduce less efficiently, while their thicker-coated, or smarter, or better camouflaged cousins flourish.

Then, over generations, the gene pool of the local community of that species does change. It contains more genes for short, climbing legs or long, running legs or short tails or long tails or whatever the local environment is now paying a premium for. Gradually, the anatomy of the average species member changes. If short-tailed members have been surviving better for the last sixty generations and long-tailed members have been dying young, before they could reproduce, the gene pool changes. Eventually, there will be many more individuals with short tails, a now-normal, genetically transmitted trait of the species.

Pondering Rex’s case helped me to absorb Darwinism. My understanding grew and then, one day, through a mental leap, I suddenly “got” the newer, better model. A model I hadn’t understood became clear, and it gave deeper coherence to all my ideas about living things. Lamarckism became just an interesting footnote in the history of Science for me, occasionally still useful because it showed me one way in which my thinking, and that of others, could go wrong.

(To be complete here, I will add that there is now some evidence that, at least in small degrees, stressing an individual can cause its genetic code to alter, though almost always only for a generation or two. This process is called “epigenetic”. But epigenetic changes and their effects on the evolution of that individual organism’s species can be neglected for our purposes here. The evidence shows by far, most of the time, Darwinian processes of variation and selection govern evolution. Bayesianism can, furthermore, accommodate epigenetic models of species change. They are just more nuances to be added to a detailed, nuanced, ever-evolving model of evolution that enables and guides research in the whole, massive field of study called “Biology”. Bayesians are comfortable with that.)

The question that now arises is this: how would the Bayesian way of choosing between the Lamarckian and Darwinian models of evolution or of reshaping one’s views on the mentally challenged compare with the Empiricist way or the Rationalist way of dealing with these same problems?

The chief danger of Empiricism that Bayesians try to avoid is the insidious slip into dogmatism. In the history of Science, many Empiricist-minded scientists have worked out and checked a theory so thoroughly that they have slipped into thinking they have found an unshakeable truth. For example, physicists in the late 1800s were in general agreement that there was little left to do in Physics. Physics, for these people, was complete. Newton and Maxwell, between them, had articulated all the truths of the physical world, from atomic to cosmic. Then, Einstein’s Theory of Relativity overthrew Newtonian Physics.

 

 

                              

                               James Clerk Maxwell (credit: Wikimedia Commons)

 

Today, Physics is in a constant state of upheaval. A few physicists still show a longing for certainty, but most modern physicists are tentative and cautious. They’ve been let down so many times in the last hundred years by theories that once had seemed so promising, but that later were shown by experiment to be flawed, that they have become permanently wary of all “truth” claims. 

It is regrettable that a similar caution has not got into more of the physicists’ fellow scientists and, more frequently, public intellectuals who promulgate and defend science to the general public. They often speak as if Darwinism explains all aspects of the living world we know about or could want to know about. But it is still only a theory; it should be viewed as tentative and likely, but not irrevocable or final. It is part of a bigger, more nuanced model of evolution that is evolving as new data are encountered. (See Dawkins and Wong. ²)

The larger point for our purposes here, however, is that while some who believe Empiricist methods can lead us to truth may present the Theory of Evolution to us as final, Bayesians never endorse any one model as the last word on anything, and they never throw out any of the old models or theories entirely. Even those that are clearly proven wrong have things to teach us, and of the ones that are currently working well, we have to say, simply, that …they are currently working well.

In contrast to Empiricism, Rationalism has other problems, especially with the whole Theory of Evolution and what was going on with my dog, Rex.

For Plato, the whole idea of a canine genetic code that contained the instructions for the making of an ideal dog would have sounded appealing. Obviously, the code must have come from the dimension of the forms, the pure Good. 

But Plato would have rejected the idea that back a few geological ages ago no dogs existed, while some other animals did exist that looked like dogs, but were not imperfect copies of an ideal dog “form.” We know now these creatures can be more fruitfully thought of as excellent examples of canis lupus variabilis, another species entirely. All dogs, for Plato, should be seen as poor copies of the ideal dog that exists in the pure dimension of the Good. But the fossil records in the rocks don’t so much cast doubt on Plato’s idealism as belie it altogether. With regard to gradual, incremental change in all species, Plato’s commitment to “forms” would have led him to totally reject Darwin’s Theory of Evolution.

In the meantime, Descartes’s version of Rationalism would have had serious difficulties with the mentally challenged. Do they have minds/souls or not? If they don’t grasp Math and Geometry and they can’t discuss “clear and distinct” ideas, are they human or are they mere animals? The abilities of the mentally challenged range from slightly below normal to severely mentally handicapped. At what point on this continuum do we cross the threshold between human and animal? Between the realm of the soul and that of mere matter, in other words?

Descartes’s ideas about what properties make a human being human are disturbing. But his ideas about how we can treat non-human creatures are revolting.

To Descartes, animals didn’t have souls; therefore, humans could do whatever they wished to them and not violate any of his moral beliefs. In his own scientific work, he dissected dogs alive. Their screams weren’t evidence of real pain, he claimed. They had no souls and thus could not feel pain. The noise was like the ringing of an alarm clock – a mechanical sound, nothing more. Generations of scientists after him performed similar acts: vivisection in the name of Science. ³

Would Descartes have stuck to his definition of what makes a being morally considerable if he had known then what we know now about the physiology of pain? Would Plato have kept preaching his form of Rationalism if he had been given access to the fossil records we have? These are imponderable questions. It’s hard to imagine either of them would have been that stubborn. But the point is that they didn’t know then what we know now. 

In any case, after considering some likely Rationalist responses to the test situations described in this chapter, it is certainly reasonable for us to say again that Rationalism’s way of portraying what human minds do when they think and know is simply mistaken.

And now, we can put aside for good our regrets about both Rationalism and Empiricism and the inadequacies of their ways of looking at the world. We can go on to a more detailed and comprehensive discussion of Bayesianism.

 

 

 

Notes

 

1. Bayes’ Formula, Cornell University website, Department of Mathematics. Accessed April 6, 2015. http://www.math.cornell.edu/~mec/2008-2009/ TianyiZheng/Bayes.html.  

 

2. Richard Dawkins and Yan Wong; Epilogue to the Mouse’s Tale – On Epigenetics; Richard Dawkins.net; June 8, 2016.

 

3. Richard Dawkins, “Richard Dawkins on Vivisection: ‘But Can They Suffer?’” BoingBoing blog, June 30, 2011.

http://boingboing.net/2011/06/30/richard-dawkins-on-v.html.

 

                             Chapter 7              Bayesianism: How It Works

 

                                

                                             

    

                                                 

                                     Thomas Bayes (credit: Wikimedia Commons)

The best answer to the problem of what human minds and human knowing are is that, in reality, we are all Bayesians. On Bayesianism, I can build a universal moral system.

So, what is Bayesianism?

Thomas Bayes was a Presbyterian minister, statistician, and philosopher who formulated the theorem named for him: Bayes’ Theorem. His theory of how humans form tentative beliefs and gradually turn those beliefs into concepts has been given several mathematical formulations, but it says a fairly simple thing.

Bayes’ Theorem says this: we tend to become more convinced of the truth of a theory or model of reality the more we keep encountering bits of evidence that, first, support the theory and, second, can’t be explained by any of the competing theories our minds already hold.¹

Under the Bayesian model, we never claim to know anything for certain. Empiricism and Rationalism both aim to provide us with a way of thinking that can lead us to unshakable truths. But Bayesianism does not claim to seek perfect truth. Instead, it says that we hold most firmly a few beliefs we consider very highly probable, and we use them as we make decisions in our lives. We then assign lesser degrees of probability to our more peripheral beliefs, and we constantly track the evidence confirming or disconfirming all our beliefs. Under Bayesianism, we accept that all beliefs, at every level of generality, need constant updating, even the ones that have been working well at guiding us to handle real life. It is far more akin to Empiricism than Rationalism, but beyond both. Agile. Alive.

For most people, in their daily lives, the more a theory enables them to establish some kind of overall order that covers all their concepts and memories, the more persuasive the theory seems. If the evidence favoring the theory mounts, and its degree of consistency with the rest of the concepts and memories in the mind also grows, then finally, in a leap of understanding, the mind promotes the theory up to the status of a belief and incorporates the new belief into its total stock of thinking machinery. Once I understand how evolution works, I see it in every living thing I pass. The same is true of gravity, respiration, etc.

At the same time, the mind nearly always has to demote to inactive status some formerly held concepts that are not commensurable with the new belief. This is especially true of all mental activities involved in the kinds of thinking that are now being covered by the new theory. For example, once you absorb and accept a theory of how your immune system works, that concept will inform every health-related decision you make thereafter – diet, supplements, exercise, etc.

In life, examples of the workings of Bayesianism can be seen all the time. All we need do is look closely at how we and the people around us make up our minds.

When I was in junior high school, each year in June, I and all the other students of the school were bussed to the city track meet at a stadium in West Edmonton. Student athletes from all the public junior high schools in the city came to compete in the biggest track meet of the year. Its being held near the end of the school year, of course, added to the excitement of the day.

A few of the athletes competing came from a special school that educated and cared for those kids who today would be called “mentally challenged”. In my Grade 9 year, three of my friends and I, on a patch of grass beside the bleachers, did a mock cheer in which we shouted the name of this school in a short rhyming chant, attempted some clumsy dance kicks in step, crashed into each other, and fell down – all in an obviously mocking style. I should make clear that I did not learn such a cruel attitude from my home. Had they seen this stunt, my parents would have been furious. But fourteen-year-olds with their peers can be cruel.

The problem was that one of the prettiest, smartest girls in my Grade 9 class, Ann, was sitting in the bleachers, watching field events in a lull between track events. She and two of her friends happened to catch our little routine. By the glares on their faces, I could see they were not amused. Later that day, I learned that she had an older brother who had attended our school and earned excellent marks, but she also had a younger brother who had Down syndrome.

I apologized lamely the next day at school, but it was clear I’d lost all chance with her. However, she said one thing that stayed with me. She told me that if you form a bond with a mentally retarded person (retarded was the word we used in those days), you will soon realize you have made a friend whose loyalty, once won, is unchanging and unshakeable – probably, the most loyal friend you will ever have. And that realization will change you.

The idea she was expressing took root. Then, over the next twenty years, it grew into a concept and finally into an absolute conviction.

                            

                  

           

              Francis Galton, originator of eugenics (credit: Wikimedia Commons)

It was the proverbial thin edge of the wedge. Earlier, I had absorbed some of the ideas of the pseudo-science called Eugenics from one of my friends at school. I’d concluded the mentally challenged added nothing of value to a community, but inevitably took a great deal out of it. They could, and should, be bred out of the human genome. What Ann said made me question those assumptions. 

Over years of seeing movies like A Child Is Waiting and Charlie, and of being exposed to awareness-raising campaigns by families of the mentally challenged, I began to see them in a different light. Over decades of changes in attitudes, they were called mentally handicapped and then mentally challenged or special needs, and the changing terminology did matter. It changed society’s thinking.

I became a teacher, and then, in the middle of my career, mentally challenged kids began to be integrated into the public school where I taught. I saw with increasing clarity what they could teach the rest of us, just by being themselves.

Tracy was severely handicapped, mentally and physically. Trish, on the other hand, was a reasonably bright girl who had rage issues. She beat up other girls, she stole, she skipped class, she smoked pot behind the school. But when Tracy came to us, Trish proved in a few weeks to be the best with Tracy of any of the students in the school. Her attentiveness and gentleness were humbling to see. In Tracy, Trish found someone who needed her; it changed everything for Trish. As I watched them together one day, it changed me. Years of persuasion and experience, by gradual degrees, finally, got to me. I saw a new order in the community in which I lived, a new view of compassion and inclusiveness that gave coherence to years of memories. We are all siblings caring for each other in a social ecosystem.

Today, I believe the mentally challenged are people. But it was only grudgingly at fourteen that I began to re-examine my beliefs about them. At fourteen, I liked believing my mind was made up on every issue. Only years of gradually growing awareness led me to change my view. A new thinking model, gradually, by accumulation of evidence, came to look more correct and useful to me than the old model. Then, in a kind of conversion experience, I switched models. Of course, by gradual degrees, through exposure to reasonable arguments and real experiences, I and a lot of other people have come a long way on the mentally challenged from what we believed in 1964. Humans can change. By Bayesian kinds of steps, I learned a new way of looking at the mentally challenged.

 

                

                              Doberman Pinscher (credit: Wikimedia Commons) 

 

 

In a more scientific example of Bayesianism working in my own thinking, I will also mention our Doberman Pinscher–cross pup. Rex was basically a good dog, but he was a mutt, a Doberman cross we acquired because one of my aunts couldn’t keep him. People often remarked that he looked like a Doberman, but his tail was not docked. This got me curious. I learned that most Dobermans had had their tails bobbed for many generations, and I wondered why the tails, after many generations of docking, had not simply become shortened at birth. I asked a Biology teacher at my high school, but his answer only confused me. Actually, I don’t think he understood the key concepts in Darwinian Evolution Theory himself.

                                    

                               Jean-Batiste Lamarck (credit: Wikimedia Commons)

Once I got to university, I took several Biology courses. Gradually at first, and then in a breakthrough of understanding, I came to realize that I had been thinking in terms of the model of evolution called Lamarckism. At first, I did not want to let go of this cherished opinion of mine. I had always thought of myself as progressive, modern, scientific; I did not believe in Creationism. I thought I knew how evolution worked. I thought I was using an understanding of it in all my thinking. It was only after I had read more and seen by experience that docking dogs’ tails did not cause their pups’ tails to be any shorter that I came to a full understanding of Darwinian evolution.