Spin more than one hypothesis. If there's something to be explained, think of all the different ways in which it could be explained. Then think of tests by which you might systematically disprove each of the alternatives. What survives, the hypothesis that resists disproof in this Darwinian selection among "multipleworking hypotheses," has a much better chance of being the right answer than if you had simply run with the first idea that caught your fancy. (Sagan, 1996, p. 210)
The more difficult and novel the problem, the greater is likely to be the amount of trial and error required to find a solution. At the same time, the trial and error is not completely random or blind; it is, in fact, rather highly selective. The new expressions that are obtained by transforming given ones are examined to see whether they represent progress toward the goal. Indications of progress spur further search in the same direction; lack of progress signals the abandonment of a line of search. Problem solving requires selective trial and error. (Simon, 1969, pp. 95-6)
. . . human problem solving, from the most blundering to the most insightful, involves nothing more than varying mixtures of trial and error and selectivity. (Simon, 1969, p. 97)
A considerable amount has been learned in the past five years about the nature of the mazes that represent common human problem-solving tasks--proving theorems, solving puzzles, playing chess, making investments, balancing assembly lines, to mention a few. All that we have learned about these mazes points to the same conclusion: that human problem solving, from the most blundering to the most insightful, involves nothing more than varying mixtures of trial and error and selectivity. The selectivity derives from various rules of thumb, or heuristics, that suggest which paths should be tried first and which leads are promising. We do not need to postulate processes more sophisticated than those involved in organic evolution to explain how enormous problem mazes are cut down to quite reasonable size. (Simon, 1969, p. 97)
We have seen that . . .In certain respects operant reinforcement resembles the natural selection of evolutionary theory. Just as genetic characteristics which arise as mutations are selected or discarded by their consequences, so novel forms of behavior are selected or discarded through reinforcement. (Skinner, 1953, p. 430)
The parallel between biological and cultural evolution breaks down at the point of transmission. There is nothing like the chromosone-gene mechanism in the transmission of a cultural practice. Cultural evolution is Lamarckian in the sense that acquired practices are transmitted. To use a well-worn example, the giraffe does not stretch its neck to reach food which is otherwise out of reach and then pass on a longer neck to its offspring; instead, those giraffes in whom mutation has produced longer necks are more likely to reach available food and transmit the mutation. But a change of culture which develops a practice permitting it to use otherwise inaccessible sources of food can transmit that practice not only to new members but to contemporaries or surviving members of an earlier generation. More important, a practice can be transmitted through "diffusion" to other cultures--as if antelopes observing the usefulness of the long neck in giraffes, were to grow long necks. Species are isolated from each other by the nontransmissibility of genetic traits, but there is no comparable isolation of cultures. A culture is a set of practices, but it is not a set which cannot be mixed with other sets. (Skinner, 1971, pp. 130-131)
The environment made its first great contribution during the evolution of the species, but it exerts a different kind of effect during the lifetime of the individual, and the combination of the two effects is the behavior we observe at any given time. Any available information about either contribution helps in the prediction and control of human behavior and in its interpretation in daily life. To the extent that either can be changed, behavior can be changed. (Skinner, 1974, p. 17)
Compared with the experimental analysis of behavior, developmental psychology stands in the position of evolutionary theory before Darwin. By the early nineteenth century it was well known that species had undergone progressive changes toward more adaptive forms. They were developing or maturing, and improved adaptation to the environment suggested a kind of purpose. The question was not whether evolutionary changes occurred but why. Both Lamarck and Buffon appealed to the purpose supposedly shown by the individual in adapting to his environment--a purpose somehow transmitted to the species. It remained for Darwin to discover the selective action of the environment, as it remains for us to supplement developmentalism in behavioral science with an analysis of the selective action of the environment.
The important thing about a culture so defined is that it evolves. A practice arises as a mutation, it affects the chances that the group will solve its problems, and if the group survives, the practice survives with it. It has been selected by its contribution to the effectiveness of those who practice it. Here is another example of that subtle process called selection, and it has the same familiar features. Mutations may be random. A culture need not have been designed, and its evolution does not show a purpose. (Skinner, 1974, p. 203)
In summary, then, human behavior is the joint product of (i) the contingencies of survival responsible for the natural selection of the species and (ii) the contingencies of reinforcement responsible for the repertoires acquired by its members, including (iii) the special contingencies maintained by an evolved social environment. (Ultimately, of course, it is all a matter of natural selection, since operant conditioning is an evolved process, of which cultural practices are special applications.) (Skinner, 1981, p. 502)
Each of the three levels of variation and selection has its own discipline--the first, biology; the second, psychology; and the third, anthropology. Only the second, operant conditioning, occurs at a speed a which it can be observed from momeoment to moment. Biologists and anthropologists study the processes through which variations arise and are selected, but they merely reconstruct the evolution of a species or culture. Operant conditioning is selection in progress. It resembles a hundred million years of natural selection or a thousand years of the evolution of a culture compressed into a very short time. (Skinner, 1981, p. 502)
A problem is posed for which we must invent a solution. We know the conditions to be met by the sought idea; but we do not know what series of ideas will lead us there. In other words, we know how the series of our thoughts must end, but not how it should begin. In this case it is evident that there is no way to begin except at random. Our mind takes up the first path that it finds open before it, perceives that it is a false route, retraces its steps and takes another direction. Perhaps it will arrive immediately at the sought idea, perhaps it will arrive very belatedly; it is entirely impossible to know in advance. In these conditions we are reduced to dependence on chance. By a kind of artificial selection, we can in addition substantially perfect our thought and make it more and more logical. Of all the ideas which present themselves to our mind, we note only those which have some value and can be utilized in reasoning. For every single idea of a judicious and reasonable nature which offers itself to us, what hosts of frivolous, bizarre, and absurd ideas cross our mind. Those persons who, upon considering the marvelous results at which knowledge has arrived, cannot imagine that the human mind could achieve this by a simple fumbling, do not bear in mind the great number of scholars working at the same time on the same problem, and how much time even the smallest discovery costs them. Even genius has need of patience. It is after hours and years of meditation that the sought-after idea presents itself to the inventor. He does not succeed without going astray many times; and if he thinks himself to have succeeded without effort, it is only because the joy of having succeeded has made him forget all the fatigues, all of the false leads, all of the agonies, with which he has paid for his success. . . . If his memory is strong enough to retain all of the amassed details, he evokes them in turn with such rapidity that they seem to appear simultaneously; he groups them by chance in all the possible ways; his ideas, thus shaken up and agitated in his mind, form numerous unstable aggregates which destroy themselves, and finish up by stopping on the most simple and solid combination. (quoted in Campbell, 1974b, p. 429)
[HOME] [NEXT]Darwin's theory explains the surprising fit between organisms and environment in terms of hidden randomness and selective retention; evolutionary epistemology uses the same sort of mechanism to explain the surprising fit between beliefs and the world. In both cases, we must also face the anomaly of apparently guided variation--the problem of complex organs in biology and of intelligent conjectures in epistemology. What we have argued in this essay is that both anomalies can be solved by an appeal to preadaptation, the application of previous adaptations, themselves the result of chance and inheritance. The model of random variation and selective retention is saved by showing that what appears to be non-random variation is in fact the result of selective retention. Some conjectures really are guided, but the guides are simply parts of the inheritance that is an essential feature of the evolutionary model. We have thus tried to save the central claim of evolutionary epistemology while at the same time preserving the strong intuition that the process by which scientists generate their hypotheses is not usually a random walk. We also hope to have provided some indication of the fruitfulness of fleshing out the analogy between epistemic and biological evolution. (Stein & Lipton, 1989, p. 53)