Tag: theory

Without criticism no progress

But the most important misunderstandings and muddles arise out of the loose way in which dialecticians speak about contradictions.

They observe, correctly, that contradictions are of the greatest importance in the history of thought—precisely as impor­tant as is criticism. For criticism invariably consists in pointing out some contradiction; either a contradiction within the theory criticized, or a contradiction between the theory and another theory which we have some reason to accept, or a contradiction between the theory and certain facts—or more precisely, between the theory and certain statements of fact. Criticism can never do anything except either point out some such contradiction, or, perhaps, simply contradict the theory (i.e. the criticism may be simply the statement of an antithesis). But criticism is, in a very important sense, the main motive force of any intellectual development. Without contradictions, without criticism, there would be no rational motive for changing our theories: there would be no intellectual progress. [424]

The stimulus to further development

As Max Planck once remarked in a lecture,

A living and flourishing theory does not avoid its anomalies but searches them out, for the stimulus to fur­ther development comes from contradiction, not from confirmations.

The point to keep in mind is that although falsifiability, rather than verifiability, is the most important criterion in determin­ing whether a theory is scientifically meaningful, its usefulness for the greater task of building confidence in a theory is limited. A theory is accepted not simply because it has withstood many attempts at falsification, the need for such tests notwithstanding, but because it leads to predictions that are experimentally verified. After all, the purpose of a theory is to be productive and not just to fail to be wrong. [115]

Gould’s view of Popperian falsification

Philosopher Karl Popper has argued for decades that the primary criterion of science is the falsifiability of its theories. We can never prove absolutely, but we can falsify. A set of ideas that cannot, in principle, be falsified is not science.

The entire creationist argument involves little more than a rhetorical attempt to falsify evolution by presenting supposed contradictions among its supporters. Their brand of creationism, they claim, is “scientific” because it follows the Popperian model in trying to demolish evolution. Yet Popper’s argument must apply in both directions. One does not become a scientist by the simple act of trying to falsify another scientific system; one has to present an alternative system that also meets Popper’s criterion—it too must be falsifiable in principle. [256]

Proposals for the scientific method

When verificationism failed, philosophers proposed that science progresses because scientists follow a method guar­anteed to lead to the truth. Proposals for the scientific method were offered by philosophers such as Rudolf Carnap and Paul Oppenheim. Karl Popper put forward his own proposal, which was that science progresses when scientists pro­pose thories that are falsifiable—that is, they make statements that can be contradicted by experiment. According to Popper, a theory is never proved right, but if it survives many attempts to prove it wrong, we can begin to have faith in it—at least until it is finally falsified. [296]

The meagre foundation of science

[E]ver since the seminal work of philosopher of science Karl Popper, for a scientific theory to be worthy of its name, it has to be falsifiable by experiments or observations. This requirement has become the foundation of the “scientific method.” [262]

Popper’s absolute theory of truth

The objective theory of truth leads to a very different attitude. This may be seen from the fact that it allows us to make assertions such as the following: a theory may be true even though nobody believes it, and even though we have no reason for accepting it, or for believing that it is true; and another theory may be false, although we have comparatively good reasons for accepting it.

Clearly, these assertions would appear to be self-contradictory from the point of view of any subjective or epistemic theory of truth. But within the objective theory, they are not only consistent, but quite obviously true.

A similar assertion which the objective correspondence theory would make quite natural is this: even if we hit upon a true theory, we shall as a rule be merely guessing, and it may well be impossible for us to know that it is true. [305]

Our method is not to prove how right we were

[T]hese marvellously imaginative and bold conjectures or ‘anticipations’ of ours are carefully and soberly controlled by systematic tests. Once put forward, none of our ‘anticipations’ are dogmatically upheld. Our method of research is not to defend them, in order to prove how right we were. On the contrary, we try to overthrow them. [278-9]

Settled science

To obtain a picture or model of this quasi-inductive evolution of science, the various ideas and hypotheses might be visualized as particles suspended in a fluid. Testable science is the precipitation of these particles at the bottom of the vessel: they settle down in layers (of universality). The thickness of the deposit grows with the number of these layers, every new layer corresponding to a theory more universal than those beneath it. As the result of this process ideas previously floating in higher metaphysical regions may sometimes be reached by the growth of science, and thus make contact with it, and settle. [277]

Corroboration and timeless truth

In the logic of science here outlined it is possible to avoid using the concepts ‘true’ and ‘false’. …

Whilst we assume that the properties of physical objects (of ‘genidentical’ objects in Lewin’s sense) change with the passage of time, we decide to use these logical predicates in such a way that the logical properties of statements become timeless: if a statement is a tautology, then it is a tautology once and for all. This same timelessness we also attach to the concepts ‘true’ and ‘false’, in agreement with common usage. It is not common usage to say of a statement that it was perfectly true yesterday but has become false today. If yesterday we appraised a statement as true which to­day we appraise as false, then we implicitly assert today that ; that the statement was false even yesterday—timelessly false—but that we erroneously ‘took it for true’.

Here one can see very clearly the difference between truth and corroboration. The appraisal of a statement as corrobo­rated or as not corroborated is also a logical appraisal and therefore also timeless; for it asserts that a certain logical relation holds between a theoretical system and some system of accepted basic statements. But we can never simply say of a statement that it is as such, or in itself, ‘corroborated’ (in the way in which we may say that it is ‘true’). We can only say that it is corroborated with respect to some system of basic statements—a system accepted up to a particular point in time. ‘The corroboration which a theory has received up to yesterday’ is logically not identical with ‘the corro­boration which a theory has received up to today’. Thus we must attach a subscript, as it were, to every appraisal of cor­roboration—a subscript characterizing the system of basic statements to which the corroboration relates (for example, by the date of its acceptance).

Corroboration is therefore not a ‘truth value’; that is, it cannot be placed on a par with the concepts ‘true’ and ‘false’ (which are free from temporal subscripts); for to one and the same statement there may be any number of different cor­roboration values, of which indeed all can be ‘correct’ or ‘true’ at the same time. For they are values which are logically derivable from the theory and the various sets of basic statements accepted at various times.

The above remarks may also help to elucidate the contrast between my views and those of the pragmatists who pro­pose to define ‘truth’ in terms of the success of a theory—and thus of its usefulness, or of its confirmation or of its corro­boration. If their intention is merely to assert that a logical appraisal of the success of a theory can be no more than an appraisal of its corroboration, I can agree. But I think that it would be far from ‘useful’ to identify the concept of corrobo­ration with that of truth.* [273-5]

* Thus if we were to define ‘true’ as ‘useful’ (as suggested by some pragmatists), or else as ‘successful’ or ‘confirmed’ or ‘corroborated’, we should only have to introduce a new ‘absolute’ and ‘timeless’ concept to play the role of ‘truth’.

Step-by-step approximations to truth

The degree of corroboration of two statements may not be comparable in all cases, any more than the degree of falsi­fiability: we cannot define a numerically calculable degree of corroboration, but can speak only roughly in terms of positive degree of corroboration, negative degrees of corroboration, and so forth. Yet we can lay down various rules; for instance the rule that we shall not continue to accord a positive degree of corroboration to a theory which has been falsified by an inter-subjectively testable experiment based upon a falsifying hypothesis. (We may, however, under cer­tain circumstances accord a positive degree of corroboration to another theory, even though it follows a kindred line of thought. An example is Einstein’s photon theory, with its kinship to Newton’s corpuscular theory of light.) In general we regard an inter-subjectively testable falsification as final (provided it is well tested): this is the way in which the asymme­try between verification and falsification of theories makes itself felt. Each of these methodological points contributes in its own peculiar way to the historical development of science as a process of step by step approximations. [266-7]