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So one nucleotide has changed in three hundred twelve hours between a rhesus monkey and man and as between yeast and man only 43 nucleotides have changed out of three hundred and twelve forty three out of three hundred and twelve. There was a day many ages ago in which yeast and men were sharing some common ancestor and then some of those ancestors went one way to eventually become yeasts. And there is. This. Took another road and eventually became a man and these this bifurcated half way. So it's really two POVs from that point at which we and one two pathways have been pursued. Oh for heaven knows how long. Perhaps a billion years and
the entire trip. There are two pathways mind you have resulted in a total change. 43 nucleotides out of three hundred and twelve. And none of us have a dreamed that there was this kind of relationship that holds together the entire world of living organisms. Here is this fantastic conservatism that needs to be coupled with this other thing I spoke of. This is sort of this anarchy that constantly invades the genetic message and the denouement. The thing that brings these things together that makes it work this way is natural selection. I once heard Niels Bohr point out and it's a very significant fact that though one has a great deal of physics concerned with
the realm of uncertainty and determinacy that. And that's specifically that micro-world that I began by mentioning Bohr was pointing out that all experiments done in the make grow. Well they determine it and that's an important consideration. Well we have something a little analogous here. One has this micro-world of the genetic message which since it is a micro world since it doesn't operate statistically but individually one thing is enough to specify one molecule nucleus presumably can specify all the protein of a certain type that the organism needs. I'm not sure of that but it looks that way. In this micro world where the situation is an archaic call
for those sort of unpredictable changes probably indeterminate changes that has to come into the world of experiment the experiment being performed in the maker of natural selection. There's nothing chance or random or indeterminate or unpredictable about natural selection. Natural selection is quite coldly and cleanly. Letting those things survives that work better and eliminating those that work less well and a great deal of that elimination of course occurs in complicated organisms before they are ever launched. All of you sitting here for example have already been screened. By the time of birth to have reached that point at which you could be born meant that things were going pretty well with you and a great deal of
elimination had already occurred as all of you realize. Yes you have been screened in a way nature by permitting you to be born vouched for you but how much of this disorder still remains. And that's an interesting question that I want to go out next. There is a principle that biologists know is the hardy Weinberg law and it's exceedingly simple. It says that in any steady state and for any mutation that's been around in human populations for quite a while it has reached a relatively steady state in any given population. If one is dealing for example with some recess of mutation if the frequency of the population is Q And there is a dominant normal characteristic and then
this is a recess of mutation so that if we call frequency a fraction of times it occurs for the dominant P the recess of q b's together equal 1. And if we look at such a population in the steady state one has it accounted for. Since your chromosomes a double and most of these genes We'll talk about are represented twice Q Square will represent the number. Presence in the population who have to have the recess of character and hence in whom it will appear you understand that if you have a recessive but also the dominant gene for the same character that dominant normal gene makes you normal so that you don't even know that you've got the recess of your carrier and
the proportion of carriers is given by this to p q. So the proportion of full dominance which are not carriers is peace and the proportion of recesses in whom this trait will show a given by Q Square. And now it's child's play to figure out the distribution within any population of such genes as this provided one knows the occurrence of some recess of mutation. So let's proceed to one of these diseases known as final ketonuria final ketonuria has a strange name because it appears in the urine. Well that wouldn't worry any body but unfortunately the children in home find it appears in the urn. These children are feeble minded and have mousy odor and
nowadays they can actually be treated with special diets but this disagreeable disease is a recess of and afflicts one child in 25000 in the United States. The proportion of carriers comes out in this simple calculation to be one in 70 for these products. This disorder in the genetic message rather widely distributed. Probably none of us escapes carrying a fair number of them. And this is of course what the trouble is with these oversimplified schemes of eugenics. This is the situation it's practically impossible to cope with because it's a hidden one. And because however drastic the selection one is never in fact touching this concealed situation that keeps it going. One can calculate very
simply the process of selecting out of the population. Some such recesses and one finds it almost hopeless. For example there's a very something that doesn't concern us at all the matter of whether one can taste finals. Some people tasted as very bitter some people don't taste it at all. It turns out that the tasting is the dominant non tasting is the recesses and in the United States 30 percent of Americans tasters this will interest all of you a great deal. And suppose I want to have the privilege of seeing to it that anybody who could not taste it is absolutely prevented from ever having any offspring. Then it turns out that it would take approximately a thousand generations not to eliminate this quite but to get it down to a tenth of 1 percent to 1 in
1000. I felt I was in generations if we consider years to a generation that gets you back to about 30000 years ago when man young men were drawing those interesting pictures on the walls of the caves. So we ran through these factors that I've spoken of the complexity the dynamic state and this constant intrusion of genetic disorder. One can be quite convinced that each living thing including every human thing is indeed an individual unlike any other in either space or time. But to that one must add something of ultimate importance. And that is that. We are history storing creatures and it is not only about each of us comes into the world with a unique
inheritance but we begin to accumulate Nique history and this history that grows throughout our lives is already so known and that self that private self is the unique composition and structure that come to us via those genes via the inheritance coupled with a unique history that is ours alone and forever growing. The basis of that storing of history because again it comes to us on two levels. Phylogenetic and ontogenetic. The basis of that storing of history as regards the evolution of the species I've already spoken to. That's the thing that ties us together with the yeast. That is this extraordinary conservatism
in our genetic makeup. But no one yet knows what the physical basis is the chemical basis is this capacity that we have as individuals to store our history to learn to remember to develop new patterns of behavior to store and make something of our experience. I would guess. At least I should be willing to assume as a hypothesis that all of that that goes into the private self both the genetic makeup and this history storing. I would be quite ready to assume that it is all determinant. One reason for my tending to believe that is that
the process is I know of in. Living organisms. Multi molecular. They usually involve millions if not billions of molecules and any process. Of that nature that does involve great numbers of molecules has a regularity that simply comes out of its statistics a regularity that would disappear the moment one window from processes involving great numbers of molecules to processes involving one or a few molecules. So it would be a very important consideration in this problem. If one had any reason to suppose that there are processes governing our behavior for example that depend upon reactions of one or a few molecules. Now I don't know of any such but it so happens
that since I do work on vision that's brought me close to the nearest approach to such a process of which I know and that is in the fact that. These little recept is in the human retina known as rockets with which one performs vision in dim light. Night vision. Those rods when completely dark adapted. We have excellent reason to believe that each rod can be stimulated by receiving by absorbing one photon. One quantum of light. I don't know of any other process throughout biology that has been demonstrated to get down to that level so that here we have in fact a one molecule process because one observes that one quantum of light is one molecule
a well known visual pigment called Red option. I don't know whether all of you quite understand why I make so much of this matter the way one molecule behaves as compared with let's say millions and billions of molecules. If I'm dealing with some reaction in which millions of billions of molecules are involved I can measure just how that reaction goes. For example I will measure the way the product of this reaction accumulates as a function of time. And starting from zero product I find as a usual thing a perfectly regular course of this reaction and the reaction that I'm describing here. We can say is a going to be be accumulating with time. Now suppose I start dividing these molecules into little separate
compartments little test tubes and I keep on dividing them until finally I have very few molecules and each test tube. Now mind you I still have it in all the test tubes all the molecules I began with so that in all the test tubes this perfectly smooth process is going on and let us assume that it's a reasonably fast process that's finished in one hour. Now if I sub divide this population of molecules to the point at which I have just one molecule per test too. And I stopped watching that one molecule. What this is saying is that at any time during an hour from the beginning of the reaction that one molecule will quite suddenly and instantaneously pop over from the state A to B. The point I'm trying to make is that when we're dealing with millions and billions of molecules and have these statistics of large numbers to deal with
ONE has this show of smoothness predictability everything's lovely. The moment you get down to one molecule it's either A or it's B. And this will be accomplished in an instant you see and it will sit as a perhaps for 40 minutes 55 minutes or it will go immediately in the first second. No way of saying but what comes as a smooth process on this statistical basis is all a nothing. Violent explosive reaction on the basis of one molecule. Hence this is an important consideration. And if it were true that our behavior depended even in part upon the reactions of single molecules of very small numbers. That would be an important consideration. That brings us back to this one instance I know of in which human rod is in fact
excited when completely dark adapted by absorbing one quantum of light. Well it turns out that that's not enough to make us see what will make us see. It is about 10 of those rods simultaneously that is within a period no greater than one hundredth of a second. And those ten rods must be together on the retina to the degree that they are within a little circle of tens. No more than about a tenth of a degree arc that under those circumstances one first sees anyone familiar with radio design will recognize that what we're dealing with here is the noise level. Here is one molecule of fare but actually I know that these molecules that we have in the retina these molecules have visual pigment
rather sensitive perishable things. And even in the complete absence of light there are many billions of them in the retina. And one of them is likely to go off at any time. And if that's all that's needed to send off one rod one rod is. And there's good evidence that this is true likely to respond at any time. But that is enough to make a see. And none of our behavior depends upon it. On the contrary there is a little insurance that when we see it has been no accident but a light has flashed because it takes 10 such events within approximately one hundredth of a second and within a very small space on the retina that contains no more than 500 rods in all for this event to enter consciousness and for us to see. So even in this closest case there is a kind of safeguard and in fact that possibility of indeterminacy is made determinate by this insistence upon a degree of simultaneity
closeness in space that in fact smoothed out that process rather well. For these and other reasons I would be glad to assume that it's all determined. And incidentally for those of you who choose to assume something else I'd like to remind you that. Proudest people are what they conceive to be their free will. They lose all that pride the moment it's necessary to make an excuse to offer an alibi. A man who is offering an alibi always does so on the basis of complete determinism. He promptly calls upon forces beyond his control and there is every show living. In a world in which he's not to be blamed for his actions. I would be perfectly willing to believe that all of it is determined but it is not something else
and that is predictable. That is here we have this extraordinarily complex Constitution. I spent a little time trying to impress you with the realisation that none of us quite knows what that is that we're carrying these genes and incidentally by now one knows that dominance are an all dominant and recesses aren't all recess of whatever Gene you have is doing something. All of us are carrying a lot of genetics that we know nothing about and are never going to find anything about. And then we are storing this history this continuous flow of experience. And when the time comes to make a decision to exercise that thing called free will to choose when the time comes. The self that is exercising free will is. I think that unique product of the unique genetics and the unique
history and at that moment no one is able to predict the outcome within limits. No it does the person making the decision. No anyone else because none of us has the requisite information. So I should say that the essence of free will is not a failure of determinism but is a failure of predictability and let me go on with this thought. How free is free will. Well it's rather curious that you use your willy all the shouting is about very narrow segment of ones experience and choice. There is a tremendous realm that is completely determined and predictable and that just permits one to live as an
organized living organism in fact that's what makes one work internally that lets one's parts function together harmoniously enough so that one goes about as a functioning living organism so there is all that internal adjustment which constitutes one's vegetative life and does not call for decisions and indeed had better not called for decision so I think it was. The strange Englishman Bolton who decided one day to perform the experiment of never drawing another breath without willing it so he went along happily with this. He will teach breath and then he drew it and then he will do next one and he drew it that he thought well I've had enough of that. So he stopped and promptly stopped breathing. And this man describes going through a highly uncomfortable space in which he having intruded upon one of the vegetative automatic functions found it a little hard to get out of the way again
and let this thing go on. There is a second an entire series of relationships that involve a more seamless fact that one must function in an environment and environment of the creatures of the same kind of creatures of other kinds food getting reproduction all the things that quite apart from one's internal organization make one function in the world. And once again there are places where these involve some choice. But there are many places I think most places and which one isn't being asked. One is told for example here at Chicago Anthony Carlson the great physiologist and at the same time Walter Cannon at Harvard are doing a classical work. Period around World War 1. Classical work on hunger and they were at great pains to point out that when they were speaking of hunger they
meant hunger and they did not mean appetite. And I think it was canon use the nice phrase appetite invites one to eat but hunger forces one to eat. And under the impetus of hunger one is no longer being invited one is being ordered and people will eat things. The most distasteful and sickening variety in fact it may make them violently ill. But they're not being asked. They're being told. And finally there is a third realm here that doesn't involve our choice fundamentally and that arises in the strange form builtin behavior in organisms that is serving not there and but the ends of the species. I'll give you one example in passing so you know the sort of thing I'm talking about. There are times when the lemming
population grows particularly. I think there just isn't enough food for the lemmings to eat and lack of food drives animals to run. And it is this that seems to be the driving impulse behind the lemming migrations as indeed all such animal hunger migrations that force us away from the center of population great hordes of lemmings many of which perish in the ocean when they get to it. We're speaking of the mountain sides of Norway. Others go wandering off on the other side of the same mountains across the plains of Lapland to perish there. But in any case the migration continues until the population has been thinned out sufficiently at its center so that there is enough food for those that remain. And with that it automatically stops and so we have these three kinds of behavior that involve I think the great bulk of our behavior and the great bulk of our
lives that ask for no decision. This internal realm the organism and its environment and then call upon the organism that is not an individual call but that of the species. So I want this free will. Is free within limits. And indeed I think the more one thinks about it the more one realizes how narrow the limits are. It's rather curious. Sometimes I think the whole nervous system is made in the form of no fibers that bifurcate could simply come in and divide in two and one side says either and the other one says or because how often does one face decisions more complex than the decisions between two alternatives. Three things to choose among. That's a frightfully complicated situation. And yet you realize by this
within what narrow constraints. Freedom of will is access. Nevertheless such as it is I think that in all truth this freedom of will. Exists though I think it exists in its essential unpredictability though probably very possibly in any case determined. I do think it's one of our most precious possessions and I think that it may become necessary for us to guard it well. You heard George Wald professor of biology at Harvard University as he spoke on the topic. Biological determinacy individuality and the problem of free will. The subject for our next program will be the science of science. Our speaker at that time will be
The Chicago lectures
George Wald, part 2
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University of Chicago
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University of Maryland (College Park, Maryland)
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This program presents the second part of a speech by George Wald of Harvard University: "Biological Determinacy, Individuality, and the Problem of Free Will."
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This series presents lectures given at University of Chicago, focusing on the nature of human beings, their place in the universe, and their potentialities. The lectures were also published in The Bulletin of Atomic Scientists, beginning in September 1965.
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Producing Organization: University of Chicago
Speaker: Wald, George, 1906-1997
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University of Maryland
Identifier: 65-40-2 (National Association of Educational Broadcasters)
Format: 1/4 inch audio tape
Duration: 00:29:54
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Chicago: “The Chicago lectures; George Wald, part 2,” 1965-09-13, University of Maryland, American Archive of Public Broadcasting (GBH and the Library of Congress), Boston, MA and Washington, DC, accessed October 23, 2021,
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APA: The Chicago lectures; George Wald, part 2. Boston, MA: University of Maryland, American Archive of Public Broadcasting (GBH and the Library of Congress), Boston, MA and Washington, DC. Retrieved from