Fitelson wrote:In Chapter 12 of Warrant and Proper Function, Alvin Plantinga constructs two arguments against evolutionary naturalism, which he construes as a conjunction of E&N. The hypothesis E says that "human cognitive faculties arose by way of the mechanisms to which contemporary evolutionary thought directs our attention" (p. 220). With respect to proposition N, Plantinga (p. 270) says "it isn't easy to say precisely what naturalism is," but then adds that "crucial to metaphysical naturalism, of course, is the view that there is no such person as the God of traditional theism."
[Of course, Plantinga is overlooking the fact that their is a difference between methodological naturalism and philosophical naturalism, and that science is based upon methodological naturalism, and it is mistaken to conflate the two. (See Pennock, p. 57)
Platinga goes on to assign subjective propabilities to his propostions, upon which there is no "objective basis for such probability assignments." (Pennock, p. 412)]
Plantinga says (p. 220, footnote 7) that his probabilities can be interpreted either "epistemically" or "objectively," but that he prefers the objective interpretation. However, Bayesians have never been able to make sense of the idea that prior probabilities have an objective basis. The siren song of the Principle of Indifference has tempted many to think that hypotheses can be assigned probabilities without the need of empirical evidence, but no consistent version of this principle has ever been articulated. The alternative to which Bayesians typically retreat is to construe probabilities as indicating an agent's subjective degree of belief. The problem with this approach is that it deprives prior probabilities (and the posterior probabilities that depend on them) of probative force. If one agent assigns similar prior probabilities to evolutionary naturalism and to traditional theism, this is entirely consistent with another agent's assigning very unequal probabilities to them, if probabilities merely reflect intensities of belief. (Fitelson et al. 2002: 411; cited in Pennock)
Although Plantinga's arguments don't work, he has raised a question that needs to be answered by people who believe evolutionary theory and who also believe that this theory says that our cognitive abilities are in various ways imperfect. Evolutionary theory does say that a device that is reliable in the environment in which it evolved may be highly unreliable when used in a novel environment. [Evo-devo is revealing new levels of plasticity in the development and adaptation of the organism.] It is perfectly possible that our mental machinery should work well on simple perceptual tasks, but be much less reliable when applied to theoretical matters. We hasten to add that this is possible, not inevitable. It may be that the cognitive procedures that work well in one domain also work well in another; Modus Ponens may be useful for avoiding tigers and for doing quantum physics. (Fitelson et al. 2002: 424-425; cited in Pennock)
Anyhow, if evolutionary theory does say that our ability to theorize about the world is apt to be rather unreliable, how are evolutionists to apply this point to their own theoretical beliefs, including their belief in evolution? One lesson that should be extracted is a certain humility--an admission of fallibility. This will not be news to evolutionists who have absorbed the fact that science in general is a fallible enterprise. Evolutionary theory just provides an important part of the explanation of why our reasoning about theoretical matters is fallible. (Fitelson et al. 2002: 425; cited in Pennock)
Far from showing that evolutionary theory is self-defeating, this consideration should lead who believe the theory to admit that the best they can do in theorizing is to do the best they can. We are stuck with the cognitive equipment that we have. We should try to be as scrupulous and circumspect about how we use this equipment as we can. When we claim that evolutionary theory is a very well confirmed theory, we are judging this theory by using the fallible cognitive resources we have at our disposal. We can do no other. (Fitelson et al. 2002: 425; cited in Pennock)
Plantinga suggests that evolutionary naturalism is self-defeating, but that traditional theism is not. However, what is true is that neither position has an answer to hyperbolic doubt. Evolutionists have no way to justify the theory they believe other than by critically assessing the evidence that has been amassed and employing rules of inference that seem on reflection to be sound. If someone challenges all the observations and rules of inference that are used in science and in everyday life, demanding that they be justified from the ground up, the challenge cannot be met. A similar problem arises for theists who think that their confidence in the reliability of their own reasoning powers is shored up by the fact that the human mind was designed by a God who is no deceiver. The theist, like the evolutionary naturalist, is unable to construct a non-question-begging argument that refutes global skepticism. (Fitelson et al. 2002: 425; cited in Pennock)
-- Fitelson, Branden and Sober Elliott. Plantinga's Probability Arguments against Evolutionary Naturalism. In Intelligent Design Creationism and Its Critics: Philosophical, Theological, and Scientific Perspectives (Robert T. Pennock, ed.). Cambridge: MIT Press; 2002; p. 411; 424-425.
Fox wrote:The steps that have been identified by experiment are:
1. Formation of amino acids from primordial reactants.
2. Formation of proteinoids by polymerization of sets of amino acid.
3. Formation of microstructures by contact of polymers with water.
4. Origin of the genetic apparatus within such microstructures.
The experimental results show that the probability of each step is close to unity .... For purposes of argument let us assume 90%, although the experiments indicate > 90%. The probability of reproductive, infrastructured cell-like entities arising in steps from inorganic matter containing atoms of carbon, hydrogen, oxygen, and nitrogen is then at least (9/10)4 = 65%. (All such "numerology," however, on either side may be considered a quantitative euphemism for ignorance.)
-- Fox, Sidney W. Creationism and Evolutionary Protobiogenesis. In Science and Creationism (Ashley Montagu ed.). Oxford: Oxford University Press; 1984; p. 212.
Kitcher wrote:Throughout his book, Behe repeats the same story. He describes, often charmingly, the complexities of molecular structures and processes. There would be nothing to complain of if he stopped here and said: "Here are some interesting problems for molecularly minded evolutionists to work on, and, in a few decades time, perhaps, in light of increased knowledge of how development works at the molecular level, we may be able to see what the precursors were like.” But he doesn’t. He tries to argue that the precursors and intermediaries required by Darwinian evolutionary theory couldn’t have existed. This strategy has to fail because Behe himself is just as ignorant about the molecular basis of development as his Darwinian opponents. Hence he hasn’t a clue what kinds of precursors and intermediaries the Darwinian account is actually committed to--so it’s impossible to demonstrate that the commitment can’t be honored. However, again and again, Behe disguises his ignorance by suggesting to the reader that the Darwinian story must take a very particular form--that it has to consist in something like the simple addition of components, for example--and on that basis he can manufacture the illusion of giving an impossibility of proof. (Kitcher 2002: 265)
Although this is the main rhetorical trick of the book, there are some important subsidiary bits of legerdemain. Like pre-Reformation creationists, Behe loves to flash probability calculations, offering spurious precision to his criticisms. Here’s his attack on a scenario for the evolution of a blood-clotting mechanism, tentatively proposed by Russell Doolittle:
“… let’s do our own quick calculation. Consider that animals with blood-clotting cascades have roughly 10,000 genes, each of which is divided into an average of three pieces. This gives a total of about 30,000 gene pieces. TPA [Tissue Plasminogen Activator] has four different types of domains. By “variously shuffling,” the odds of getting those four domains together is 30,000 to the fourth power, which is approximately one-tenth to the eighteenth power, and if a million people played the lottery each year, it would take an average of about a thousand billion years before anyone (not just a particular person) won the lottery…. Doolittle apparently needs to shuffle and deal himself a number of perfect bridge hands to win the game.” (DBB 94) (Kitcher 2002: 265-266)
This sounds quite powerful, and Behe drives home the point by noting that Doolittle provides no quantitative estimates, adding that “without numbers, there is no science” (DBB 95)--presumably to emphasize that born-again creationists are better scientists than the distinguished figures they attack. But consider a humdrum phenomenon suggested by Behe’s analogy to bridge. Imagine that you take a standard deck of cards and deal yourself thirteen. What’s the probability that you got exactly those cards in exactly that order? The answer is 1 in 4 x 1021. Suppose you repeat this process ten times. You’ll now have received ten standard bridge hands, ten sets of thirteen cards, each one delivered in a particular order. The chance of getting those cards in just that order is 1 in 410 x 10210. This is approximately 1 in 10222. Notice that the denominator is far larger than that of Behe’s trifling 1018. So it must be really improbable that you (or anyone else) would ever receive just those cards in just that order in the entire history of the universe. But, whatever the cards were, you did. (Kitcher 2002: 266)
What my analogy shows is that, if you describe events that actually occur from a particular perspective, you can make them look improbable. Thus, given a description of the steps in Doolittle’s scenario for the evolution of TPA, the fact that you can make the probability look small doesn’t mean that that isn’t (or couldn’t) have been the way things happened. One possibility is the evolution of blood-clotting was genuinely improbable. But there are others. (Kitcher 2002: 266)
Return to your experiment with the deck of cards. Let’s suppose that all the hands you were dealt were pretty mundane--fairly evenly distributed among the suits, with a scattering of high cards in each. If you calculated the probability of receiving ten mundane hands in succession, it would of course be much higher than then priority of being dealt those very particular mundane hands with the cards arriving in just that sequence (although it wouldn’t be as large as you might expect). There might be an analogue for blood-clotting, depending on how many candidates there are among the 3,000 “gene pieces” to which Behe alludes that would yield a protein able to play the necessary role. Suppose that there are a hundred acceptable candidates for each position. That means that the chance of success on any particular draw is (1/30)4, which is about 1 in 2.5 million. Now, if there were 10,000 tries per year, it would take, on average, two or three centuries to arrive at the right combination, a flicker of an instant in evolutionary time. (Kitcher 2002: 266-267)
Of course, neither Behe nor I know how tolerant the blood-clotting system is, how many different molecular ways it allows to get the job done. Thus we can’t say if the right way to look at the problem is to think of the situation as an analogue to being dealt a very particular sequence of cards in a very particular order, or whether the right comparison is with cases in which a more general type of sequence occurs. But these two suggestions don’t exhaust the relevant cases. (Kitcher 2002: 267)
Suppose you know the exact order of cards in the deck prior to each deal. The probability that the particular sequence would occur would be extremely high (barring fumbling or sleight of hand, the probability would be 1). The sequence only looks improbable because we don’t know the order. Perhaps that’s true for the Doolittle shuffling process as well. Given the initial distribution of pieces of DNA, plus the details of the biochemical milieu, principles of chemical recombination might actually make it very probable that the cascade Doolittle hypothesizes would ensue. Once again, nobody knows whether this is so. Behe simply assumes that it isn’t. (Kitcher 2002: 267)
Let me sum up. There are two questions to pose: What is the probability that the Doolittle sequence would occur? What is the significance of a low value for that probability? The answer to the first question is that we haven’t a clue: it might be close to 1, it might be small but significant enough to make it likely that the sequence would occur in a flicker of evolutionary time, or it might be truly tiny (as Behe suggests). The answer to the second question is that genuinely improbable things sometimes happen, and one shouldn’t confuse improbability with impossibility. Once these points are recognized, it’s clear that, for all its rhetorical force, Behe’s appeal to numbers smacks more of numerology than of science. As with his main line of argument, it turns out to be an attempt to parlay ignorance of molecular details into an impossibility proof. (Kitcher 2002: 267)
-- Kitcher, Philip. Born-Again Creationism. In Intelligent Design Creationism and Its Critics: Philosophical, Theological, and Scientific Perspectives (Robert T. Pennock, ed.). Cambridge: MIT Press; 2002; pp. 265-267.
Kitcher's argument cuts both ways for both scientists and religionists; one shouldn't confuse so-called probability with certainty, nor should one attempt to parlay ignorance of the true origin of life based upon "pure speculation" into the possibility of proof, such as Wald attempts below:
Wald wrote:About a century ago the question, How did life begin?, which has interested men throughout their history, reached an impasse. Up to that time two answers had been offered: one that life had been created supernaturally, the other that it arises continually from the nonliving. The first explanation lay outside science, the second was now shown to be untenable. For some time scientists felt some discomfort in having no answer at all. Then they stopped asking. Recently ways have been found again to consider the origin of life as a scientific problem--as an event within the order of nature. In part this is the result of new information. But a theory never rises of itself, however rich and secure the facts. It is an act of creation. Our present ideas in this realm were first brought together in a clear and defensible argument by the Russian biochemist A. I. Oparin in a book called The Origin of Life, published in 1936. Much can be added now to Oparin's discussion, yet it provides the foundation upon which all of us who are interested in this subject have built. (Wald 1968: 337)
(....) At the center of the enterprise lies the hope not only of explaining a great past event--important as that should be--but of showing that the explanation is workable. If we can indeed come to understand how a living organism arises from the nonliving, we should be able to construct one. (...) This is so remote a possibility now that one scarcely dares to acknowledge it; but it is there nevertheless. (Wald 1968: 337)
One answer to the problem of how life originated is that it was created. This is an understandable confusion of nature with technology. Men are used to making things; it is a ready thought that those things not made by men were made by a superhuman being. (Wald 1968: 337)
(....) The reasonable view was to believe in spontaneous generation; the only alternative, to believe in a single, primary act of supernatural creation. There is no third position. For this reason many scientists a century ago chose to regard the belief in spontaneous generation as a "philosophical necessity." It is a symptom of the philosophical poverty of our time that this necessity is no longer appreciated. Most modern biologists, having reviewed with satisfaction the downfall of the spontaneous generation hypothesis, yet unwilling to accept the alternative belief in special creation, are left with nothing. (Wald 1968: 339)
I think a scientist has no choice but to approach the origin of life through a hypothesis of spontaneous generation. What the controversy ... showed to be untenable is only the belief that living organisms arise spontaneously under present conditions. We have now to face a somewhat different problem: how organisms may have arisen spontaneously under different conditions in some former period, granted that they do so no longer. (Wald 1968: 339)
The Task
To make an organism demands the right substance in the right proportions and in the right arrangement. We do not think that anything more is needed. (....) (Wald 1968: 340)
The Possible and Impossible
One has only to contemplate the magnitude of this task to concede that the spontaneous generation of a living organism is impossible. Yet here we are--as a result, I believe, of spontaneous generation. [a priori 'philosophical' position taken on belief and faith.] It will help to digress for a moment to ask what one means by "impossible." (Wald 1968: 339-40)
With every event one can associate a probability--the chance that it will occur. This is always a fraction, the proportion of times the event occurs in a large number of trials. Sometimes the probability is apparent even without trial. A coin has two faces; the probability of tossing a head is therefore ½. A die has six faces; the probability of throwing a deuce is 1/6. When one has no means of estimating the probability beforehand, it must be determined by counting the fraction of successes in a large number of trials. (Wald 1968: 340)
Our everyday concept of what is impossible, possible or certain derives from our experience: the number of trials that may be encompassed within the space of a human lifetime, or at most within recorded human history. In this colloquial, practical sense I concede the spontaneous origin of life to be “impossible.” It is impossible as we judge events in the scale of human experience. (Wald 1968: 340)
We shall see that this is not a very meaningful concession. For one thing, the time with which our problem is concerned is geological time, and the whole extent of human history is trivial in the balance. We shall have more to say of this later. (Wald 1968: 340)
But even within the bounds of our own time there is a serious flaw in our judgment of what is possible. It sounds impressive to say that an event has never been observed in the whole of human history. We should tend to regard such an event as at least “practically” impossible, whatever probability is assigned to it on abstract grounds. [a priori grounds] When we look further into such a statement, however, it proves to be almost meaningless. For men are apt to reject reports of very improbable occurrences. Persons of good judgment think it safer to distrust the alleged observer of such an event than to believe him. The result is that events which are merely very extraordinary acquire the reputation of never having occurred at all. Thus the highly improbable is made to appear impossible. (Wald 1968: 340)
To give an example: Every physicist knows that there is a very small probability, which is easily computed, that the table upon which I am writing will suddenly and spontaneously rise into the air. The event requires no more than that the molecules of which the table is composed, ordinarily in random motion in all directions, should happen by chance to move in the same direction. Every physicist concedes this possibility; but try telling one that you have seen it happen. Recently I asked a friend, a Nobel laureate in physics, what he would say if I told him that. He laughed and said that he would regard it as more probable that I was mistaken than that the event had actually occurred. (Wald 1968: 340)
We see therefore that it does not mean much to say that a very high improbable event has never been observed. There is a conspiracy to suppress such observations, not among scientists alone, but among all judicious persons, who have learned to be skeptical even of what they see, let alone of what they are told. If one group is more skeptical than others, it is perhaps lawyers, who have the harshest experience of the unreliability of human evidence. Least skeptical of all are the scientists, who, cautious as they are, know very well what strange things are possible. (Wald 1968: 340)
A final aspect of our problem is very important. When we consider the spontaneous origin of a living organism, this is not an event that need happen again and again. It is perhaps enough for it to happen once. The probability with which we are concerned is of a special kind; it is the probability that an event occur at least once. To this type of probability a fundamentally important thing happens as one increases the number of trials. However improbable the event in a single trial, it becomes increasingly probable as the trials are multiplied. Eventually the event becomes virtually inevitable. (Wald 1968: 340)
For instance, the chance that a coin will not fall head up in a single toss is 1/2. The chance that no head will appear in a series of tosses is 1/2 x 1/2 x 1/2 … as many times over the number of tosses. In 10 tosses the chance that no head will appear is therefore 1/2 multiplied by itself 10 times, or 1/1,000. Consequently the chance that a head will appear at least once in 10 tosses is 999/1,000. Ten trials have converted what started as a modest probability to a near certainty. (Wald 1968: 340)
The same effect can be achieved with any probability, however small, by multiplying sufficiently the number of trials. Consider a reasonably improbable event, the chance of which is 1/1,000. The chance that this will not occur in one trial is 999/1,000. The chance that it won’t occur in 1,000 trials is 999/1,000 multiplied together 1,000 times. This fraction comes out to be 37/100. The chance that it will happen at least once in 1,000 trials is therefore one minus this number--63/100--a little better than three chances out of five. One thousand trials have transformed this from a highly improbable to a highly probable event. In 10,000 trials the chance that this event will occur at least once comes out to be 19,999/20,000. It is now almost inevitable. (Wald 1968: 340)
It makes no important change in the argument if we assess the probability that an event occur at least two, three, four or some other small number of times rather than at least once. It simply means that more trials are needed to achieve any degree of certainty we wish. Otherwise everything is the same. (Wald 1968: 340-341)
In such a problem as the spontaneous origin of life we have no way of assessing the probabilities beforehand or even of deciding what we mean by a trial. The origin of a living organism is undoubtedly a stepwise phenomenon, each step with its own probability and its own conditions of trial. Of one thing we can be sure, however: whatever constitutes a trial, more such trials occur the long the interval of time. (Wald 1968: 341)
The important point is that since the origin of life belongs in the category of at-least-once phenomena, time is on its side. However improbable we regard this event, or any other steps which it involves, given enough time it will almost certainly happen at least once. And for life as we know it, with its capacity for growth and reproduction, once may be enough. (Wald 1968: 341)
Time is in fact the hero of the plot. The time with which we have to deal is of the order of two billion years. What we regard as impossible on the basis of human experience is meaningless here. Given so much time, the “impossible” becomes possible, the possible probable, and the probable virtually certain. One has only to wait: time itself performs the miracles. (Wald 1968: 341)
-- Wald, George. The Origin of Life. In The Molecular Basis of Life: An Introduction to Molecular Biology. (Readings From Scientific American, ed.).: Freeman; 1968; pp. 337-341.
As Fox notes, "All such 'numerology,' however, on either side may be considered a quantitative euphemism for ignorance."
