Biology deals, notoriously, with complex systems. In discussing biological methodology, all three papers in this symposium honor the complexity of biological subject matter by preferring models and theories built to reflect the details of complex systems to models based on broad general principles or laws. Rheinberger's paper, the most programmatic of the three, provides a framework for the epistemology of discovery in complex systems. A fundamental problem is raised for Rheinberger's epistemology, namely, how to understand the referential continuity of the theoretical terms and concepts employed in typical case studies involving complex systems.

Understanding the role mechanistic constraints play in shaping evolution can relieve the tension between the generally accepted intuition that there are no strict laws in biology and empirical findings showing that evolutionary processes are biased toward preferred outcomes. Mechanistic constraints explain why some evolutionary outcomes are more probable than others and allow for predictions in specific lineages. At the same time, mechanistic constraints are neither necessary nor universal in the way laws are traditionally characterized: they remain contingent on the past evolution of the biological mechanisms underpinning them and only constrain the future evolution of the organisms possessing them.

1. Introduction. Attempts to utilize the probability calculus to prove or disprove various inductive or inductive skeptical theses are, I believe, highly problematic. Inductivism and inductive skepticism are substantive (logically consistent) philosophical positions that do not allow of merely formal proofs or disproofs. Often the problems with particular alleged formal proofs of inductive or inductive sceptical theses turn on subtle technical considerations. In the following I highlight such considerations in pointing out the flaws of two proofs, one an alleged proof of an inductive sceptical conclusion due to Karl Popper, the other an alleged proof of an inductivist thesis originally due to Harold Jeffreys and later advocated by John Earman. Surprisingly, in examining Popper's argument it is shown that certain apparently weak premises, often embraced by both inductivists and deductivists, lend themselves to inductive conclusions. However it is argued that those premises are still philosophically substantive and not amenable to a purely formal demonstration. The lesson to be learnt here is twofold. First, we need to be very careful in determining which formal theses entail, and which are entailed by, inductive skepticism and inductivism. Second, we need to take great care in laying out and examining the assumptions presumed in formal arguments directed for and against such formal theses. In a follow up article I will consider various attempts by David Stove and Karl Popper and David Miller to identify the exact content of inductive skepticism and propose a new identification based on the theory of content developed in Gemes 1994. Finally I will compare this new version with that proposed recently in Alberto Mura 1990.

Starting with a discussion of what I call ‘Koyré's paradox of conceptual novelty’, I introduce the ideas of Damerow et al. on the establishment of classical mechanics in Galileo's work. I then argue that although their view on the nature of Galileo's conceptual innovation is convincing, it misses an essential element: Galileo's use of the experiments described in the first day of the Two New Sciences. I describe these experiments and analyze their function. Central to my analysis is the idea that Galileo's pendulum experiments serve to secure the reference of his theoretical models in actually occurring cases of free fall. In this way, Galileo's experiments constitute an essential part of the meaning of the new concepts of classical mechanics.

“Accessibility” is a crucial concept of possible worlds semantics. The simplest approach to accessibility is the “magical theory” that construes this relation as analogous to spatial or temporal relations. In this paper I give a nonmagical structural account of the accessibility relation that can be used to give a necessitarian account of kinds and laws. Laws are characterized in a structural way as stable invariants of the world's gestalt. Finally, I point out how the structural approach can be embedded in a general representational theory of modality.

A proper understanding of black hole complementarity as a response to the information loss paradox requires recognizing the essential role played by arguments for the applicability and limitations of effective semiclassical theories. I argue that this perspective sheds important light on the arguments advanced by Susskind, Thorlacius, and Uglum—although ultimately I argue that their position is unsatisfactory. I also consider the argument offered by 't Hooft for the breakdown of microcausality around black holes, and conclude that it relies on a mistaken treatment of measurement collapse. There is, however, a legitimate argumentative role for black hole complementarity, exemplified by the position of Kiem, Verlinde, and Verlinde, that calls for a more subtle analysis of the limitations facing our effective theories.

Based on the historical case of galvanic experimentation in Germany, I identify five types of experimentation which explored and shaped the new phenomenon rather than tested theoretical predictions. Verification evaluated initial reports of Galvani's phenomenon. Simplification reduced the experimental protocol to the fewest and most basic steps. Optimization found experimental conditions that magnified the observed effect. Exploration tested a wide variety of metals, animals or configurations. Application modified the experiment to address unresolved related problems. Attempts to derive laws of the phenomenon or establish its underlying causes were unsuccessful primarily due to the great variability of the experimental results.

Professor Feigl's admirably lucid and concise appraisal of the major considerations which are still significant in the controversy between realism and phenomenalism includes the important reminder that the problem at hand should be viewed as concerning, not the truth or falsity of two conflicting hypotheses, but rather the comparative adequacy of two alternative proposals for the rational reconstruction of scientific knowledge. Feigl advocates the approach of semantic realism in preference to a phenomenalistic type of reconstruction on the grounds that in his critical examination, the latter has been “found wanting,” whereas semantic realism—and only semantic realism—can provide a satisfactory systematic account of the meaning and the experiential foundation of scientific hypotheses. While I fully agree with Feigl's general appraisal of the issues involved, I have doubts as to the superiority of the proposed realistic interpretation, and I should like to state these here in outline.

The concept of scaffold is widespread in science and increasingly common in evolutionary biology. While this concept figures in causal explanations, it is not clear what scaffolds are and what role they play in those explanations. Here we present evolutionary scaffolding explanation as a distinct type of explanatory strategy, distinguishing it from other types of evolutionary explanation. By doing so, we clarify the meaning of “scaffold” as a causal concept and its potential contribution to accounts of evolutionary novelty and major transitions.

Computer scientists have provided a distinct justification of Occam’s Razor. Using the probably approximately correct framework, they provide a theorem that they claim demonstrates that we should favor simpler hypotheses. The argument relies on a philosophical interpretation of the theorem. I argue that the standard interpretation of the result in the literature is misguided and that a better reading does not, in fact, support Occam’s Razor at all. To this end, I state and prove a very similar theorem that, if interpreted the same way, would justify the contradictory Anti-Occam’s Razor—the principle that we should favor more complex hypotheses.

Although the introduction of the modern axiomatic method in physics is attributed to Hilbert, it is only recently that physicists and mathematicians have applied it significantly, i.e. on a basis extensive enough to promise fruitful results. Carnap, for one, stresses the importance of the axiomatic method, yet he considers its application in physics as a task for the future.

The use that the scientist makes of his principles is well known. In the normal course of scientific investigation, a hypothesis which explains some physical phenomenon adequately in every particular, but which runs counter to, say, the laws of inertia, cannot be held without further experimentation. Such experimentation must continue until the irreconcilability of the hypothesis with the laws is resolved. In most cases the hypothesis will fail to submit to further tests, will be declared inadequate, and will give way to a new one.

When an experimenter uses the experimental method to investigate the effects of the experimenter's expectancy it may be that this research, too, is affected by his expectancy and thus there is an expectancy paradox. To the extent that the experimenter expectancy effect accounts for the variation in the dependent variable and is general, that is to say, universal in psychological research, the expectancy paradox is ineluctable. However, an analysis of the research reviews extant in this area yields the conclusion that expectancy effects are neither inexorable nor highly general in psychological research and this provides the basis for its extrication from the expectancy paradox.

This is an interesting, well argued, and highly readable book; anyone interested in the central philosophical problems with which it deals will benefit from studying it.

Stalnaker defines inquiry as the process of forming, testing, and revising beliefs. His goal is to lay the groundwork for a theory of inquiry, by elaborating and defending a certain apparatus in terms of which the process of inquiry should be described.

Describing a physical system in idealized terms involves making claims about the system that we know to be literally false. Because of this, it is not clear how calculations involving idealizations can generate justified belief and explain facts about the world. I argue that this puzzling aspect of idealizations cannot be explained away by talking about approximations, as is often supposed. I develop a different account of how justified beliefs and explanations can be generated from idealized descriptions of physical systems. My account involves a type of contextualism about the truth of mathematical descriptions of physical systems.

The axiom of comparability has been a fundamental part of mathematical choice theory from its beginnings. This axiom was a natural first assumption for a theory of choice originally constructed to explain decision making where other assumptions such as continuous divisibility of choice spaces could legitimately also be made. Once the generality of application of formal choice theory becomes apparent, it also becomes apparent that both continuity assumptions and the axiom of comparability may be unduly restrictive and lead to the neglect of decision situations which are important and which can be handled on a modified axiom set. These considerations bear on the philosophical analysis of the concept of rational decision.