A theory may be invalid, not owing to erroneous observations or the invocation of an inappropriate law, but because of the use of equivocal terms. This is demonstrated for Darwin's failed model of sympatric speciation through the principle of divergence.

Researchers often pursue proof of concept research, but criteria for evaluating such research remain poorly specified. This article proposes a general framework for proof of concept research that knits together and augments earlier discussions. The framework includes prototypes, proof of concept demonstrations, and post facto demonstrations. With a case from theoretical evolutionary genetics, the article illustrates the general framework and articulates some of the reasoning strategies used within that field. This article provides both specific tools with which to understand how researchers evaluate models in theoretical evolutionary genetics and general tools that apply to proof of concept research more generally.

The laws of nature have an internal explanatory structure. This leads to interesting questions for metaphysicians of laws. What is the nature of this explanation? Marc Lange has recently argued in favor of metalaws: higher-order laws governing other laws, of which symmetry principles may be an example. Lange argues that his view, unlike its competitors, can make sense of the explanatory power of symmetries. I agree with Lange about the explanatory structure of laws but disagree with him about the nature of this explanation. I then present a Humean view that neatly captures the explanatory power of symmetry principles.

In a survey of information theory and some of its implications, Warren Weaver has proposed a distinction between engineering (or channel) noise and semantic noise (1: 94–117). Ordinary Spanish usage reflects this distinction quite neatly. If A speaks to B and B responds with no entiendo, it means ‘I have not heard your words, because of interfering sound or lack of attention; please transmit the same message again’; if he responds with no comprendo, it means ‘I heard you all right, but what I heard doesn't make sense; please paraphrase or explain.’ Channel noise, thus, is the responsible factor when that which leaves a transmitter is not that which reaches the receiver; semantic noise is a discrepancy between the codes used by transmitter and receiver.

In his valuable book [3], Israel Scheffler presents an extended critique of Thomas Kuhn's philosophy of science. Scheffler argues against Kuhn's “main thesis,” namely that “... paradigm change in science is not generally subject to deliberation and critical assessment” ([3], p. 89). Scheffler does recognize, though, that there are important elements of Kuhn's view that themselves seem to conflict with this “main thesis.” For these elements seem to make possible deliberation, critical assessment, and objectivity in the discussion of scientific paradigms. So it appears from Scheffler's critique that Kuhn's position is inconsistent. The puzzle is compounded by Kuhn's admission—indeed, insistence—that his book does contain “a preliminary codification of good reasons for theory choice. These are ... reasons of exactly the kind standard in philosophy of science: accuracy, scope, simplicity, fruitfulness, and the like” ([1], p. 231). In his recent reply to (and further critique of) Kuhn, Scheffler quotes this passage from Kuhn and says: “If these reasons are not ... to be construed as utterly free of all constraints or themselves paradigm-dependent, then they allow the comparison of rival paradigms and make paradigm debates intelligible. Such intelligibility is, however, at odds with Kuhn's statement that the proponents of competing paradigms ‘will inevitably talk through each other’” ([4], p. 369). In this interchange between Scheffler and Kuhn, one gets the impression of people, if not paradigms, talking “through each other.” I think that this nonmeeting of minds is due to interpreting Kuhn as an opponent of objectivity when in fact he is not an opponent but a proponent. It is this misinterpretation which produces the apparent inconsistency in Kuhn's position. In this paper I suggest a way of understanding Kuhn which resolves this apparent inconsistency in his work and might help to focus discussion on the real issue between Kuhn and many of his critics. This suggestion has the crucial consequence of shifting the focus from objectivity to the real issue, namely truth.

It is the thesis of this paper that the term scientific law can and should mean in the social sciences exactly what it means in any of the other sciences. There seems to be considerable agreement among scientists as well as others that a scientific law is a generalized and verifiable statement, within measurable degrees of accuracy, of how certain events occur under stated conditions. If I were to attempt a more specific statement I would say that a law is (1) a group of verbal or mathematical symbols (2) designating an unlimited number of defined events in terms of a limited number of reactions (3) so that the performance of specified operations always yields predictable results within measurable limits.

According to Mohan Matthen and Edwin Levy, certain immunological processes require explanations in which the immune system is attributed intentional states. This, they think, strengthens the scientific credentials of intentional psychology and undermines the position of those who argue that the scientific treatment of human action should involve the elimination of intentional description. In this paper, I argue that immunology does not and need not employ intentional explanation or description and consequently has nothing to offer those who seek to defend the scientific standing of intentional psychology by looking for other disciplines that “accommodate the intentional”.

It has always been the ideal of science to discover laws of nature on which we can all agree. Agreement requires evidence independent of individual judgment, i.e., objective evidence. We apply the term objective to such unbiased scientific evidence because we associate it with an external world of objects that we conceive to be the origin of our information. This external world is instinctively invented by each of us as a means of dealing with invariant patterns in his private world of experience. The invention is validated and elaborated as a consequence of the fact that it turns out to be sharable. In fact the common content of all our invented external worlds is so unambiguous and independent of individual bias that it can form the universally accepted basis for communication and action in an organized society. The consistency of the patterns of experience associated with the external world is such that we are under severe psychological compulsion to assign to this world an existence independent of our experience and a reality superior to that of any small part of our experience. Physical science is devoted to the study of the “laws” of the external physical universe, i.e., to the behaviour of the objects in it. Hence there is a strong tendency to project into the external world the information gathered by scientifically objective methods and even the theoretical concepts in terms of which the information is interpreted. Whatever is so projected is objective in a second sense of the term, i.e., assigned by us to the external world of objects.

1. The philosophical version of the primary-secondary distinction concerns (a) the ‘real’ properties of matter, (b) the epistemology of sensation, and (c) a contrast challenged by Berkely as illusory.

The scientific version of the primary-secondary distinction concerns (a′) the physical properties of matter, (b′) a contrast essential within the history of atomism, and (c′) a contrast challenged by 20th century microphysics as de facto untenable.

2. The primary-secondary distinction within physics can be interpreted in two ways:

a. it can refer to content; e.g. ‘Matter has the properties of mass, shape, density… etc. — it only appears to have the properties of warmth, fragrance, etc.’ Or,

b. it can refer to form; e.g. ‘Whatever properties our best theories accord to primary matter, e.g., electrons, these are by definition primary. All other properties of, e.g., macromatter, are derivative.’

Concerning 2.a., this interpretation is simply false when 17th, 18th, or 19th century values for the property-variables are introduced. Concerning 2.b., this either uninformative or misleading. It is uninformative when it constitutes no more than a decision to use the word ‘primary’ as an umbrella-word for all the properties contemporary micro-physics accords to fundamental material particles, whatever these may be. It is misleading when it turns on an implicit contrast between certain properties particles may be said to have when ‘harnessed’ to a detector, and certain other properties these particles have when free and unharnessed to any detector. This contrast does not exist. Quantum-theoretic information is always about particles-and-their-detectors-in-combination. Dissolve this combination and you destroy any possible knowledge of the particle. Hence the notion of ‘completely objectifiable properties of particles’ is in principle unsound. (Cf. Hanson, American Journal of Physics, 27 January, 1959).

It is argued that two aspects of the progress of mature science characterize, at least in combination, no other fields; hence, that these aspects can usefully serve as a demarcation criterion. Scientific progress is: (1) cumulative, regardless of crisis or revolution, from the viewpoint of concrete applications; (2) capable of unrestricted growth towards universal coerciveness of argument and evidence. Before these aspects of progress are discussed, some clarifications are made and corrections offered to Kuhn's view of the nature of scientific progress across revolutions; afterwards, the suggested criterion is used to distinguish, concretely, various fields from science. Finally, it is shown that the “style” of scientific progress is not a useful demarcation criterion.

A special merit of Professor Feigl's stimulating essay lies in the clarity with which he draws the issue between phenomenalistic and realistic interpretations of science as one concerned entirely with the evaluation of their relative adequacy as analytic reconstructions of empirical knowledge. Responsible and fruitful discussion of these interpretations cannot therefore be a debate over the truth or falsity of scientific theories. For as he carefully notes, the differences between these alternative analyses are not “pragmatic differences” of the ordinary sort, since no differences in regard to any observable consequences that could weigh for or against a scientific theory can be associated with them. Feigl's own rejection of phenomenalism and his espousal of semantic realism must in consequence also be judged in terms of the standard he himself has recognized as alone relevant in this discussion.

In this essay I critically examine the role of entropy of mixing in articulating a macroscopic criterion for the sameness and difference of chemical substances. Consider three cases of mixing in which entropy change occurs: isotopic variants, spin isomers, and populations of atoms in different orthogonal quantum states. Using these cases I argue that entropy of mixing tracks differences between physical states, differences that may or may not correspond to a difference of substance. It does not provide a criterion for the sameness and difference of substance that is appropriate to chemistry.

The paper∗∗ discusses the problems raised by the inexactness of experiential concepts for a deductivist account of theoretical explanation. The process of theoretical explanation is explicated in terms of the devising of exact forms of inexact concepts. Analysis of the adjustments of concepts and their exact forms to each other reveals an implicit criterion of adequacy for theories which is related to the principle of connectivity.

Encyclopaedism” is the systematically pursued activity within the Unity of Science Movement, devoted to the collecting of scientific statements of the logic of science (synonymous with “Philosophy of Science” for Carnap and other representatives of modern Logical Empiricism) logic, mathematics, physics, biology and other sciences, including all the “cross connections” between the given disciplines. (See: Otto Neurath, Unified Science as Encyclopedic Integration; in: International Encyclopedia of Unified Science, Vol. I, No. I.)

I invoke the conceptual machinery of contemporary possible-world semantics to provide an account of the metaphysical status of “bridge laws” in intertheoretic reductions. I argue that although bridge laws are not definitions, and although they do not necessarily reflect attribute-identities, they are supervenient. I.e., they are true in all possible worlds in which the reducing theory is true.

We summarize the evidence and arguments usually employed against the use of the profit maximization assumption in microeconomic theory, and then pass directly to the methodological arguments. Two arguments are considered. The first summarizes positions which have been taken by various defenders of the “people who think a theory should be given up just because it is false are naive and confused” view. To rebut this view, we develop a scheme for classifying theoretical assumptions and show that the specious plausibility of the argument in question derives from ignoring the distinctions we have drawn. The second argument attempts to show that a better theory is more likely to be attained by continuing the development of the orthodox theory. We show that this view is mistaken and then discuss steps which have been taken to develop a better theory.

Thesis : Art like science radically affects our perceiving and thinking, and the two are substantially alike in that together—along with an inherited “natural” language system with which they overlap—they enable us to articulate the world.

Science has been advanced as the measure of all things: scientific realism. By implication, art pertains to beauty, science truth. Science effects conceptual breakthroughs, changes our models of natural order. On the contrary (I argue), as a nonverbal symbol system art similarly affects paradigm-induced expectations. Substantively there is no difference in the way each enables us to articulate or measure the world : symbolic realism.

The myth of resemblance as a criterion of representation—imitation as a one-one relation—has, at least since the time of Plato, obscured this truth. Once the distinction between representational and nonrepresentational art falls, the true nature of artist (like scientist) as maker is illumined. The artist, the scientist (disciplinarian), the cosmologist (those responsible for the formulation of so-called natural languages—in time all of us) make the world or, what practically amounts to the same thing, the known, perceived world. This is the claim of the symbolic realist. Is symbolic realism itself only a watershed ? What implication does this critique have for assessing the role of the philosopher today?

The goal of evolutionary theory is to (a) specify the general causal structure of evolving systems and (b) analyze evolutionary consequences that are expected to result from the proposed structure of the model systems. Biologists frequently emphasize the hypothetico-deductive method in evolutionary theory. I will show that this method primarily provides a tactical device for (b), while evolutionary synthesis requires a foundation of a unifying conceptual model for (a). Therefore, any successful strategy for a new synthesis requires both a new conceptual insight of evolving systems, and tactical devices for analyzing new specific aspects of the evolutionary process.

Using a variety of different results from the literature, I show how causal discovery with experiments is limited unless substantive assumptions about the underlying causal structure are made. These results undermine the view that experiments, such as randomized controlled trials, can independently provide a gold standard for causal discovery. Moreover, I present a concrete example in which causal underdetermination persists despite exhaustive experimentation and argue that such cases undermine the appeal of an interventionist account of causation as its dependence on other assumptions is not spelled out.

In this paper, I answer a fundamental question facing any view according to which natural selection is a population-level causal process—namely, how is the causal process of natural selection related to, yet not preempted by, causal processes that occur at the level of individual organisms? Without an answer to this grounding question, the population-level causal view appears unstable—collapsing into either an individual-level causal interpretation or the claim that selection is a purely formal, statistical phenomenon. I argue that a causal account of realization provides an answer to the grounding question. By applying this account of realization to the natural selection of melanism in rock pocket mice, I show how an alternative, formal account of realization, favored by proponents of the statistical interpretation, misses biologically important features. More generally, this paper shows how metaphysical issues about realization normally discussed in the philosophy of mind apply to debates in philosophy of biology. Thus, it is a first step toward fleshing out the oft-noted similarities between debates in these areas.