“What do we mean by ‘explaining’ anything? This is a problem of considerable theoretical and practical importance. First of all, every science is concerned with explanation, and it should be as important to ask what is being done, in attempting to explain a phenomenon, as to ask what particular explanation is most satisfactory. Secondly, it has practical importance in that men differ as to what explanations are satisfactory, and whether it is necessary every to go beyond the bounds of one science to find a satisfactory explanation of a phenomenon which at first sight seems clearly to belong to that science.

Perhaps the hardest blow was struck at the the theory of explanation by Hume and later by quantum physicists. Previously, it had at least been held that explanation was concerned with finding the causes of events. Hume denied that we could ever point to any ideas of ‘causality’, i.e. ‘necessary connection’ as apart from mere continual succession; and modern physics seems to say, in effect, that it has no use for causality since causality would hold only for immeasurable quantities and unobservable objects, if it held at all; and the purpose of science is taken to be the making of verifiable statements and predictions, rather than hypothesis about unobservables.

It is possible that the meaning of ‘explanation’ is different for different people (…). His particular ideal, felt rather than known, determines the kind of experiments he will choose to do, and the kind of answer he will accept. Nevertheless, there is a large field of explanation that is common to most men. Explanations are not purely subjective things (…).

The question why one explanation or another should seem satisfactory involves the prior question why any explanation at all should be sought after and found satisfactory. It is clear that, in fact, the power to explain involves the power of insight and anticipation, and that this is very valuable as a kind of distance-receptor in time, which enables organisms to adapt themselves to situations which are about to arise. Apart from this utilitarian value it is likely that our thought processes are furstrated by the unique, the unexplained and the contradictory and that we have an impulse to resolve this state of frustration, whether or not there is any practical application (…).

There are, then, five main attitudes to the problems of knowledge and explanation: A priorism, which asserts certain facts and principles to be self-evident or certain, and deduces a great body of supposed knowledge therefrom; Scepticism, which denies the legitimacy of these first principles, and questions some or all of the foundations of the belief in an external world and causal interaction; Descriptive theories, which assert that explanation is ‘generalized description’ but never tells us anything about the causes of events; Relational theories (represented by modern physics), which declare themselves to be uninterested in whether causal action between supposed ultimate units may be taking place, on the ground that things are unobservable and hence unpredictable; and that the aim of science is to find relations between observable entities which are constantly obeyed and hence permit successful predictions to be made. The foundation of this method is the association of definite probabilities, smaller than unity, with events. Finally, there are Causal theories, which hold that the events we see are the consequences of the interaction of external objects according to definite and certain rules.”

Kenneth Craik

[The Nature of Explanation]