Nature to be commanded must be obeyed; and that which in contemplation is as the cause is in operation as the rule.

To ask whether there really are electrons is the same – from the Ramsey point of view – as asking whether quantum physics is true. The answer is that, to the extent that quantum physics has been confirmed by tests, it is justifiable to say that there are instances of certain kinds of events that, in the language of the theory, are called ‘electrons’.

Einstein stated that a theory’s truth can never be proved, as future experience may contradict it. A theory can only be shown incorrect, through logical failure or contradiction by a fact. Intuition alone can decide between two competing theories agreeing with the facts.

In contrast to the mathematical concept, however, in empirical science the characteristic difference emerges that the construction which within mathematics arrives at a fixed end, remains in principle incompleteable within experience. But no matter how many ‘strata’ of relations we may superimpose on each other, and however close we may come to all particular circumstances of the real process, nevertheless there is always the possibility that some co-operative factor in the total result has not been calculated and will only be discovered with the further progress of experimental analysis.

If time is objective the physicist must have discovered that fact, if there is Becoming the physicist must know it; but if time is merely subjective and Being is timeless, the physicist must have been able to ignore time in his construction of reality and describe the world without the help of time. […] If there is a solution to the philosophical problem of time, it is written down in the equations of mathematical physics.

Perhaps it would be better to say that the solution is to be read between the lines of the physicist’s writings. Physical equations formulate specific laws […] but philosophical analysis is concerned with statements about the equations rather than with the content of the equations themselves.

If we consider the difference there is between natural philosophers, and other men, with regard to their knowledge of phenomena, we shall find it consists not in an exacter knowledge of the efficient cause that produces them, for that can be no other than the will of the Deity; but only in a greater and more enlarged comprehension, by which analogies, harmonies, and agreements are described in the works of nature, and the particular effects explained; that is, reduced to general rules, which rules grounded on the analogy and uniformness observed in the production of natural effects, are more agreeable, and sought after by the mind; for that they extend our prospect beyond what is present, and near to us, and enable us to make very probable conjectures, touching things that may have hap­pened at very great distances of time and place, as well as to predict things to come; which sort of endeavour towards omniscience is much affected by the mind.

They [i.e. students of nature] learned that reason has insight only into that which it produces after a plan of its own, and that it must not allow itself to be kept, as it were, in nature’s leading-strings, but must itself show the way with principles of judgement based upon fixed laws, constraining nature to give answer to questions of reason’s own determining. Accidental observations, made in obedience to no previously thought-out plan, can never be made to yield a necessary law, which alone reason is concerned to discover. Reason, holding in one hand its principles, according to which alone concordant appearances can be admitted as equivalent to laws, and in the other hand the experiment which it has devised in conformity with these principles, must approach nature in order to be taught by it. It must not, however, do so in the character of a pupil who listens to everything that the teacher chooses to say, but of an appointed judge who compels the witnesses to answer questions which he has himself formulated.

In scientific practice the real confirmation questions always involve the comparison of two theories with each other and with the world, not the comparison of a single theory with the world. In these three-way comparisons, [extraordinary] measurement has a particular advantage.

The man who embraces a new paradigm at an early stage must often do so in defiance of the evidence provided by problem-solving. He must, that is, have faith that the new paradigm will succeed with the many large problems that confront it, knowing that the older paradigm has failed with a few.

Structuralism’s basic ontological assumptions are as follows:

(1) There are scientific theories (in at least three different senses of the term ‘theory’).

(2) Scientific theories are cultural objects of a rather abstract kind in the sense that they are not spatiotemporally localized the way macroscopic physical objects are. Their ontological status is similar to that of other abstract cultural objects like languages [..], symphonies, computer programs, and the like.

(3) In a way similar to other abstract cultural objects, scientific theories have a ‘deep structure’. This means that their identity criteria and essential components cannot be detected in a straightforward manner by just ‘looking at’ the surface appearance of the concrete objects (e.g scientific texts) instantiating them. To display them is a non-trivial task.

(4) Scientific theories are genidentical entities. They have a ‘life’ of their own, like persons or nations do.

(5) Scientific theories are not ‘monads’. They are essentially related to things outside themselves. At least part of this outside world consists of other scientific theories. This means that there are intertheoretical relations and that they belong to the ‘essence’ of scientific theories.

As for structuralism’s specific methodology, its choice is, in part, prompted by the previous ontological assumptions.

(6) The best way to reveal the deep structure of a scientific theory as an abstract entity is by means of formal analysis. As far as possible, formal techniques of analysis and reconstruction should be preferred to explications in ordinary language. […]

(7) More specifically, given the kind of conceptual analysis required by structuralism, the most adequate formal tool, because of its universal character, appears to be set theory. […]