Rejoinder to Professor Teller

At the outset of his comments Professor Teller expresses disquiet at what seems to him my claiming to have a rule which is capable of automatically generating the hypothesis to be adopted when given nothing but the experimental data. Such a claim would indeed be quite preposterous since everybody knows that there are no clear-cut principles for the production of hypotheses, but that these are suggested by the imaginative insights of a high talent which conjectures without the aid of any rules of scientific discovery. Subsequently, he expresses the hope that I may not have had such a claim in mind. I have, of course, explicitly explained at considerable length that I wish to make a sharply different claim. I have been dealing with a situation where a hypothesis to account for all the observations had already been suggested by a scientist. But as soon as this is done, one can mechanically generate out of the suggested hypothesis infinitely many parasitic rival hypotheses by the simple method I have described. The principle of maximum parsimony determines which one to adopt among these hypotheses. But let me come to the truly surprising part of Professor Teller's paper, which is his expression of puzzlement by what is meant by extraneous evidence. He says: "[Wjhat is to count as genuine evidence and what extraneous to the evidence? Why should not the outcome of drawing lots or the word of a specially designated person (Professor Schlesinger's examples of extraneous information) simply count as part of the evidence to be used in evaluating hypotheses?" (p. 344) Although I find it almost impossible to believe that Professor Teller should not himself be able to answer this question, let me briefly reply: When we are, for example, searching for a hypothesis correlating the time traveled by a particle and the distance covered during that time, then the fact that in three seconds the particle traveled four feet I take as genuine evidence supporting the hypothesis which shall be admitted as a candi-