For the sake of clearness we shall condense the substance of the thought into a brief form: The vital nerve of science, the condition under which alone it can exist, is unprepossession, that is, a straightforward honesty that knows of no other consideration than to aim at the truth for its own sake. The believer, the Catholic, cannot be unprepossessed, because he must pay regard to dogmas and Church-doctrine and precept. Therefore he is wanting in the most essential requisite of true science. Hence college professors of a Catholic conviction are anomalous: they have no right to claim a chair in the home of unprepossessed science. For reasons of expediency it may be advisable to appoint some of them, but they cannot be regarded as sterling scientists. Catholic theology, building upon faith, is not science in the true sense of the word, and deserves no place in a university. A Catholic university, a home of scientific research built upon a Catholic foundation, is something like a squared circle. It may be that Catholic scientists, too, have their achievements, but they cannot be [pg 123] expected to be possessed of that unflinching pursuit of the truth which must be part of the man of science.
These are thoughts which have petrified in the minds of many into self-evident principles, with all the obstinacy of intolerance. It is not difficult to recognize in it the old reproach we have already dealt with, it is here in a slightly different form. The believing scientist is not free to search for the truth, being tied down by his duty to believe. Science, however, must be free. Hence the believer cannot properly pursue science.
Freedom of science and science unprepossessed are related terms and are often used synonymously. Therefore, in putting the probe to the often-repeated demand for unprepossession, we shall meet with ideas similar to those we have already discussed, only in a slightly different shape.
What, then, is that unprepossession which science must avow? Can the Catholic, the believing scientist, possess it? Unprepossessed research—“I don't like the expression,” says a representative of free-thought, “because it is a product of that shortcoming which has already done great damage to free-thought in its struggle with the powers of the past” (Jodl). Hence we have reason to fear that the confidence with which this word is used is greater than the clearness of thought it represents.
What is meant by saying that science must be unprepossessed? Undoubtedly it means that science should make no presuppositions, it must enter upon its work free from prejudice and presumption. And what is presumption? Evidently something presumed, upon which the research is to rest the level and rule of its direction: the supposition being taken for granted, without express proof. What I have expressly proved in my process of thought is no longer a supposition to the structure of thought, but a part of that structure.
Is the scientist, however, to allow no presumption at all? That would be impossible. When making his calculations the mathematician presupposes the correctness of the multiplication table. Or is he first to prove that twice three are six? He could not do it, because it is immediately self-evident. In his optical experiments in the laboratory, in drawing inferences as [pg 124] to the nature of light from different indications, the physicist presupposes that senses are able to observe the facts correctly, that everything has its respective reason, that nothing can be and not be, at the same time, under the same conditions. Can he or must he try first to prove it? He must presume it because it is beyond a doubt, and because it cannot be proved at all, at least all of it cannot. The astronomer, too, makes unhesitating use of the formulas of mathematics without examining them anew; every natural scientist calmly presupposes the correctness of the results established by his predecessors and goes on building upon those results: he may do so because he cannot with reason doubt them. Hence presumptions are common; they may be made when we are convinced of their truth; they must be made because not everything can be proved. Much cannot be proved because it is immediately self-evident, as, for instance, the ability to recognize the true or the elementary principles of reasoning; many other things cannot always be proved minutely, because not every scientist cares to begin with the egg of Leda. He that wants to build a house builds upon a given base; if he will not accept it, if he desires to dig up the fundament to the very bottom, in order to lay it anew, he will be digging forever, but the house will never be built.
Hence to say that science must be unprepossessed cannot mean that it must not make any presupposition. What, therefore, does it mean? Simply this: Science must not presume anything to be true which is false, nor anything as proved which is still uncertain and unproved. Whatever the scientist knows to be certain he may take as such, presuming it as the foundation and direction of further work; and what he knows to be probable he may suppose to be probable.
In so doing he in no way offends against the ideal that should be ever-present to his mind—the truth, because he merely allows himself to be guided by the truth, recognized as such. And the sequence of truth cannot but be truth, the sequence of certainty cannot but be certainty. But should he presuppose to be true what is false and unproved, and the uncertain to be certain, then he would offend against truth, against the aim of every science.
Hence if the critic of the Bible presupposes miracles and prophecies to be impossible, inferring therefrom that many narratives in Holy Writ cannot be authentic, but must be legends of a later period, he is making arbitrary presuppositions, he is not an unprepossessed scientist. Likewise, if an historian presupposing God's supernatural providence over the world to be impossible, and, in building upon this basis, comes to the conclusion that the Christian religion grew from purely natural factors, from Oriental notions and myths, from Greek philosophy and Roman forms of government, he again makes unproved suppositions. If the natural philosopher assumes that there cannot be a personal Creator, and infers from it that the world is of itself and eternal, he has forfeited the claim of being an unprepossessed scientist, and by making in any way his own pet ideas the basis of his research he is violating the demands of unprepossession; the results he arrives at are not scientific results, but the speculations of an amateur.