The “demarcation problem,” the issue of how to separate science from pseu- doscience, has been around since fall 1919—at least according to Karl Pop- per’s (1957) recollection of when he first started thinking about it. In Popper’s mind, the demarcation problem was intimately linked with one of the most vexing issues in philosophy of science, David Hume’s problem of induction (Vickers 2010) and, in particular, Hume’s contention that induction cannot be logically justified by appealing to the fact that “it works,” (...) as that in itself is an inductive argument, thereby potentially plunging the philosopher straight into the abyss of a viciously circular argument. (shrink)

The term pseudoscience refers to a highly heterogeneous set of practices, beliefs, and claims sharing the property of appearing to be scientific when in fact they contradict either scientific findings or the methods by which science proceeds. Classic examples of pseudoscience include astrology, parapsychology, and ufology; more recent entries are the denial of a causal link between the HIV virus and AIDS or the claim that vaccines cause autism. To distinguish between science and pseudoscience is part of what the philosopher (...) Karl Popper referred to as the demarcation problem, a project that has been dismissed by another philosopher, Larry Laudan, but that keeps gathering much interest in philosophers, scientists, educators, and policymakers. This entry provides the basics of the debate about demarcation, as well as a brief discussion of why it is of vital importance not just intellectually but for society at large. (shrink)

This paper examines the challenge that psychoanalytic theory cannot be refuted. It does so by considering the theory in its orthodox Freudian form, and in the main branches into which it can be divided ? the theory of Instincts, of Development, of Psychic Structure, of Mental Economics or Defence, and of Symptom Formation. The essential character of the generalizations and concepts of these branches will just be indicated; and we shall ask of each branch whether it is possible to refute (...) it. A considerable amount of scientific enquiry has been done into the concepts and generalizations of psychoanalysis. Relevant examples of these enquiries will be noted; and the question asked whether these scientific studies have in fact done anything to refute or support the various branches of psychoanalytic theory. The general upshot will be that the challenge is both important and a mistake. (shrink)

Kolmogorov's account in his [1933] of an absolute probability space presupposes given a Boolean algebra, and so does Rényi's account in his [1955] and [1964] of a relative probability space. Anxious to prove probability theory ‘autonomous’. Popper supplied in his [1955] and [1957] accounts of probability spaces of which Boolean algebras are not and [1957] accounts of probability spaces of which fields are not prerequisites but byproducts instead.1 I review the accounts in question, showing how Popper's issue from and how (...) they differ from Kolmogorov's and Rényi's, and I examine on closing Popper's notion of ‘autonomous independence’. So as not to interrupt the exposition, I allow myself in the main text but a few proofs, relegating others to the Appendix and indicating as I go along where in the literature the rest can be found. (shrink)

We intend to put into question two fundamental principles adopted by critical rationalism. One of them, explicitly proposed by Popper, argues that what is valid in logic is also in psychology. And the other, tacitly espoused, implies that epistemological verdicts have metascientific authority and validity. Regarding the second, we hold the view that to the conclusions arrived at by epistemology should not automatically be conferred metascientific authority and validity. To acquire metascientific import such conclusions also need to be derived from (...) the observation of the actual ways of producing scientific knowledge. The Hume-dependent manner with which Popper rejects induction exemplifies with emblematic strength the tendency to extend the conclusions of epistemology to philosophy of science. On one hand Popper endorses Hume’s argument about the lack of epistemic justification for induction, on the other, disagrees with the humean view that induction is routinely employed and should, therefore, be seen as a human or animal fact. Popper departs from Hume to argue that induction is not even a way of thinking; therefore, it can be employed neither by the layman nor by the scientist. Also in defense of the thesis that induction does not exist, Popper gives primacy to epistemology. More than an epistemological thesis, the theory that decrees that induction is not even a psychological fact requires empirical confirmation. For Popper being right, it is necessary to verify the theory that our minds always operate according to the model from the top down. And psychology not even provides the corroboration of Popper’s thesis. (shrink)

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Probabilities may be subjective or objective; we are concerned with both kinds of probability, and the relationship between them. The fundamental theory of objective probability is quantum mechanics: it is argued that neither Bohr's Copenhagen interpretation, nor the pilot-wave theory, nor stochastic state-reduction theories, give a satisfactory answer to the question of what objective probabilities are in quantum mechanics, or why they should satisfy the Born rule; nor do they give any reason why subjective probabilities should track objective ones. But (...) it is shown that if probability only arises with decoherence, then they must be given by the Born rule. That further, on the Everett interpretation, we have a clear statement of what probabilities are, in terms of purely categorical physical properties; and finally, along lines laid out by Deutsch and Wallace, that there is a clear basis in the axioms of decision theory as to why subjective probabilities should track these objective ones. These results hinge critically on the absence of hidden-variables or any other mechanism (such as state-reduction) from the physical interpretation of the theory. The account of probability has traditionally been considered the principal weakness of the Everett interpretation; on the contrary it emerges as one of its principal strengths. (shrink)

Despite its explanatory clout, the theory of evolution has thus far compiled a modest record with respect to predictive power—that other major hallmark of scientific theories. This is considered by many to be an acceptable limitation of a theory that deals with events and processes that are intrinsically random. However, whether this is an inherent restriction or simply the sign of an incomplete theory is an open question. In an attempt to help answer that question, we propose a classification scheme (...) for several types of prediction that might occur with regard to evolutionary systems, then explore the nature of these predictions in a system that simulates the evolution of neural architectures. This provides a platform from which to consider the relevance of such observations for real biological systems and illuminates a variety of key issues pertaining to prediction in those environments. (shrink)

What is the place of Psychoanalytic Theory on our map of knowledge and belief? Various alternatives are considered. Is it a scientific theory? — a myth? — or like a prescientific example of natural philosophy? — a branch of medical knowledge? — a premature empirical synthesis that is an approximation to the truth? Each of these answers runs into objections and difficulties, some of which are examined or noted. On the assumption that it is a provisional story which approximates to (...) the truth, the question is then raised: what can we do to find out how much of an approximation to the truth the theory really is? The relevance and value of psychological studies are discussed; and the suggestion is made that the status of Psychoanalytic Theory will remain an ambiguous one for some time to come. (shrink)

The relevance of different concepts of computer software (henceforth SW) rights is analysed from the viewpoint of divergent sociopolitical doctrines. The question of software rights is considered from the ontological assumptions, on one extreme, to the relevance of current practical applications of SW rights (such as copyright and patent), on the other extreme. It will be argued (from a non-descriptive/non-cognitive account) that the current expression of SW rights in Western societies (namely copyright, excluding patent) can be seen to be fair (...) from the viewpoint of the theses of agreed rights and universalisability. Finally, given that such practice is neither immoral, nor irrelevant-but fair (based on the ad ignorantiam argument)-we have good reason to respect it rather than violate or demolish it. (shrink)

Explores James’s concept of the individual in terms of physiology, psychology, philosophy, and religion.

Karl R. Popper, Professor of Logic and Scientific Method in the University of London, is primarily a physicist and a philosopher of science. In this capacity, he is interested in: the criterion demarcating science from pseudo-science, the method of science, and especially the method of social sciences. He thinks the method employed there is the cause of the trouble, since it is based on a misunderstanding of the method used in the physical sciences.