During these five war years science has proclaimed and demonstrated its role as Hercules. It has employed as its loudspeaker the bursting bomb, and as its courier the swift vehicle. Its blows have been instantly lethal.

Next, science has shown its skill as the fabricator of useable goods. And, lastly the giant has revealed some of its mild and even compassionate moods as the binder of man's mortal wounds and the healer of his fevers and mental abberations.

Recently I was asked by a somewhat disillusioned but well informed official of one of the important Foundations how long I thought it would be before we attained Utopia. My reply was that I thought we would make substantial progress toward a better world within the next one hundred years.

The reply to this, as the reader may surmise, was that my estimate was much too optimistic, the intimation being that anyone who hopes for such rapid progress in this world must be rather naive in practical matters. Such a judgment represents a widely prevailing view, but one which is supposed to be “realistic.” According to this view, social advancement is a slow business. It will be said that there is no evidence that we are much better off than the ancients. Rather than that we have progressed beyond antiquity, we find that we, as of old, have our evidences of social degradation and maladjustment. Crimes, wars, unemployment, divorce, racial and religious conflicts, even W. P. A. projects—all these are as old as recorded history. Man cannot hope to go far in the next one hundred years because in the last one thousand years he has not improved his lot in terms of fundamental human values. All he has done is multiply his gadgets and invent some new ones. Perhaps—my critic opined—we can make some headway in the next thousand years, but it will be a slow and painful process.

We must begin by distinguishing between sciences and empirical fields. The empirical fields are the elementary divisions of the natural world into levels for purposes of examination. The sciences consist in the method of examining those fields, together with the presuppositions and findings of such a method. Throughout this essay, we shall consider only the empirical fields as the subject-matter of the sciences, and the way in which the sciences describe their subject-matter, but not the sciences themselves. Thus the adjective “physical” will be employed, for instance, to describe the physical empirical field, and not “physics” to describe the science.

“All experience is an arch wherethro’ gleams” an untravell'd world and through which come the joyous adventures of life and also grief and pain. Since all that we know and hope to know and think we know must come through this arch and since the primary task of science is the validation and enlargement of knowledge, science is vitally interested in this experience and its interpretation. This interest stems not from the philosopher's epistemology but it is strictly operational. We want to know what kind of experience yields reliable knowledge when checked against other experience and applied in practical adjustment to things as they are and to prediction of the probable future course of events. In short, the field of natural science (empirical as distinguished from normative science like mathematics) embraces everything that comes within the range of human experience. Its specific functions are to codify this mixed experience, to search out those uniformities which yield classification, verification and prediction, and from these observed uniformities to construct by sound reasoning verifiable laws, hypotheses and theories, that is, to find the meaning of the experiences had. First we want to know the facts, but what we are after in the upshot is the interpretation of the facts.

Among the various meanings in which the word ‘probability’ is used in everyday language, in the discussion of scientists, and in the theories of probability, there are especially two which must be clearly distinguished. We shall use for them the terms ‘probability1’ and ‘probability2'. Probability1 is a logical concept, a certain logical relation between two sentences (or, alternatively, between two propositions); it is the same as the concept of degree of confirmation. I shall write briefly “c” for “degree of confirmation,” and “c(h, e)” for “the degree of confirmation of the hypothesis h on the evidence e“; the evidence is usually a report on the results of our observations. On the other hand, probability2 is an empirical concept; it is the relative frequency in the long run of one property with respect to another. The controversy between the so-called logical conception of probability, as represented e.g. by Keynes, and Jeffreys, and others, and the frequency conception, maintained e.g. by v. Mises and Reichenbach, seems to me futile. These two theories deal with two different probability concepts which are both of great importance for science. Therefore, the theories are not incompatible, but rather supplement each other.

1. The problem. The concept of confirmation of an hypothesis by empirical evidence is of fundamental importance in the methodology of empirical science. For, first of all, a sentence cannot even be considered as expressing an empirical hypothesis at all unless it is theoretically capable of confirmation or disconfirmation, i.e. unless the kind of evidence can be characterized whose occurrence would confirm, or disconfirm, the sentence in question. And secondly, the acceptance or rejection of a sentence which does represent an empirical hypothesis is determined, in scientific procedure, by the degree to which it is confirmed by relevant evidence.

The philosopher who is interested in developments of modern physics may turn with some profit to an argument that has recently evolved between the late George Birkhoff and Hermann Weyl. Birkhoff and his associates have constructed a theory of relativity differing in various ways from Einstein's general theory. Weyl (1) has offered a critical analysis of the Birkhoff theory along with a defense of the Einstein theory; and Birkhoff (2) has presented his rebuttal to Weyl.

Positivists since the time of Comte have defined objectivity in science in terms of the absence of prejudice on the part of the scientist towards the phenomena with which he deals. It has been assumed that if the observer would contemplate the facts himself, this objectivity—an absence of bias—could be attained. However, social psychologists, notably C. H. Cooley and G. H. Mead, have shown that this is not necessarily the case. In the study of culture, an outstanding positivist, W. G. Sumner, in his discussion of folkways and mores, has shown that this objectivity is impossible to attain. These men have described the process through which objects arise in one's experience, and come to be defined in terms of that experience, so that the same object may mean different things to different people. This seems to be the case with certain areas of social theory.

Laski has been and remains one of the most erudite and influential of the English liberals—indeed, regardless of which of his books the liberal reads, he finishes it with the feeling that Laski is a force for good in political life. However, for the kind of philosopher who is accustomed to make distinctions between morality, ethics, ideology, and descriptive science, there are certain confusions in Laski's writings that give grounds for criticism of both a theoretical and practical nature.