The Inference That Makes Science by Ernan McMullin

Abstract

BOOK REVIEWS The Inference That Makes Science. By ERNAN McMULLIN. The Aquinas Lecture, 1992. Milwaukee: Marquette University Press, 1992. Pp. iv +112. In this ambitious lecture Father Ernan McMullin recapitulates and refines a thesis that has guided his thought for the past forty years. In essence the thesis is this: precisely how science is made has eluded the best minds for centuries, and only in the work of Charles Sanders Peirce, suitably emended by McMullin, has the puzzle finally been solved. " Retroduction " is the inference that makes science. Once this is understood, errors on what constitutes scientific method-those of Aristotle, Aquinas, Galileo, Newton, Bacon, Hume, et al.-can be rectified and one can see science for what it truly is: a complex process of theory appraisal that yields, not definitive truth, but well-established results to which assent can be given with at best "practical certainty," whatever that might be (pp. 91-96). Why McMullin should have chosen such a theme for an Aquinas Lecture is a question that defies reasonable answer. Surely one does not have to he so negative about the thought of Aristotle, Aquinas, and Galileo to advance one's ideas about science in the present day. What McMullin could easily have done, and he hints at this in the last two paragraphs of his lecture (pp. 97-98), is show how retroduction is itself simply a relaxed version of the demonstrative regress, the method actually endorsed by Aristotle, Aquinas, and Galileo. Such a retroductive version, fair enough, yields knowledge of a probable cause, the type of knowledge most typical of modern science. McMullin did not have to embark on the dangerous course of trying to prove that proof and certainty are forever beyond the grasp of science, or that never in the history of science has anyone established a definitive truth. That, in effect, is what McMullin has tried to do, and in the attempt to make the point he fumbles at almost every juncture throughout a very long lecture. To set the record straight more than a review is being re--·quested; perhaps a book, and even that might not suffice for those whose minds are made up. To understand the import of the lecture one must appreciate that it is hut a brief episode in a debate over demonstration in science that has been going on since McMullin first came to the University of Notre Dame in 1954. I myself have published many hooks and articles that engage the very point of his lecture and provide the contra evidence to 131 132 BOOK REVIEWS show elements of continuity in scientific method from Aristotle to the present. My last two volumes, in press at the same time as McMullin's Aquinas Lecture, answer in detail the aporiai he there raises.1 I need 1 Galileo's Logic of Discovery and Proof. The Backgrnund, Content, and Use of His Appropriated Treatises on Aristotle's Posterior Analytics. Boston Studies in the Philosophy of Science 137. Dordrecht-Boston-London: Kluwer Academic Publishers, 1992, xxiii + 323 pp.; Galileo's Logical Treatises. A Translation, with Notes and Commentary, of His Appropriated Questions on Aristotle's Posterior Analytics. Boston Studies in the Philosophy of Science 138. DordrechtBoston -London: Kluwer Academic Publishers, 1992, xix + 239 pp. only refer the interested reader to them for an extended and documented reply to his arguments. Some idea of the flavor of our debate, however, can be gained from the following. To support his thesis, McMullin has to maintain that Aristotle's proof that the moon is a sphere (from its having phases) and that Galileo's proofs that there are mountains on the moon, that Jupiter has satellites, and that Venus circles the sun (all based on telescopic observations) are not strictly demonstrative, that is, they do not yield true and certain conclusions. He declines to answer a query I have often tendered whether he personally is certain on the basis of pre-spacecraft evidence that the moon is a sphere, that there are mountains on it, that Jupiter has satellites, and so on. Instead he offers the categorical response "that planetary science is not an apodictic science , indeed that no natural science is...