Online research in philosophy

This paper discusses abductive reasoning---that is, reasoning in which explanatory hypotheses are formed and evaluated. First, it criticizes two recent formal logical models of abduction. An adequate formalization would have to take into account the following aspects of abduction: explanation is not deduction; hypotheses are layered; abduction is sometimes creative; hypotheses may be revolutionary; completeness is elusive; simplicity is complex; and abductive reasoning may be visual and non-sentential. Second, in order to illustrate visual aspects of hypothesis formation, the paper describes recent work on visual inference in archaeology. Third, in connection with the evaluation of explanatory hypotheses, the paper describes recent results on the computation of coherence.

Biographical studies have shown that visual mental imagery plays a significant role in the conduct of scientific research, particularly in the generation of hypotheses. But the nature of visual mental imagery and its participation in abductive inference is not systematically understood. This paper discusses examples of visual abductive reasoning by archaeologists, analyzing them according to the visual information and the process of inference employed. This work supports the conclusion that visual abduction is useful to scientists under certain conditions and that it is amenable to detailed study.

In a recent study of astrophysical “fine-tunings” (or “coincidences”), Robert Klee critically assesses the support that such astrophysical evidence might be thought to lend to the design argument (i.e., the argument that our universe has been designed by some deity). Klee argues that a proper assessment indicates that the universe is not as “fine-tuned” as advertised by proponents of the design arguments. We argue (i) that Klee’s assessment of the data is, to a certain extent, problematic; and (ii) even if Klee’s assessment of the data is correct, it provides a necessary but not a sufficient response to the design argument. However, an adequate skeptical rejoinder to the design argument can be made by appealing to the anthropic principle.

The argument from design stands as one of the most intuitively compelling arguments for the existence of a divine Creator. Yet, for many scientists and philosophers, Hume's critique and Darwin's theory of natural selection have definitely undermined the idea that we can draw any analogy from design in artifacts to design in nature. Here, we examine empirical studies from developmental and experimental psychology to investigate the cognitive basis of the design argument. From this it becomes clear that humans spontaneously discern purpose in nature. When constructed theologically and philosophically correctly, the design argument is not presented as conclusive evidence for God's existence but rather as an abductive, probabilistic argument. We examine the cognitive basis of probabilistic judgments in relationship to natural theology. Placing emphasis on how people assess improbable events, we clarify the intuitive appeal of Paley's watch analogy. We conclude that the reason why some scientists find the design argument compelling and others do not lies not in any intrinsic differences in assessing design in nature but rather in the prior probability they place on complexity being produced by chance events or by a Creator. This difference provides atheists and theists with a rational basis for disagreement.

The design argument is one of three main arguments for the existence of God; the others are the ontological argument and the cosmological argument. Unlike the ontological argument, the design argument and the cosmological argument are a posteriori. And whereas the cosmological argument can focus on any present event to get the ball rolling (arguing that it must trace back to a first cause, namely God), design theorists are usually more selective.

duction; so we think it prudent to proceed with a certain diffidence. That our own account of abduction is itself abductive is methodological expression of this diffi- dence. A second objective is to test our conception of abduction’s logical structure against some of the more promising going accounts of abductive reasoning.

The motivation behind the collection of papers presented in this THEORIA forum on Abductive reasoning is my book Abductive Reasoning: Logical Investigations into the Processes of Discovery and Explanation. These contributions raise fundamental questions. One of them concerns the conjectural character of abduction. The choice of a logical framework for abduction is also discussed in detail, both its inferential aspect and search strategies. Abduction is also analyzed as inference to the best explanation, as well as a process of epistemic change, both of which chal-lenge the argument-like format of abduction. Finally, the psychological question of whether humans reason abduc-tively according to the models proposed is also addressed. I offer a brief summary of my book and then comment on and respond to several challenges that were posed to my work by the contributors to this issue.

Realism about the external world enjoys little philosophical support these days. I rectify this predicament by taking a relatively pragmatist line of thought to defend commonsense realism; I support commonsense realism through an interpretation and application of Donald Davidson’s notion of triangulation, the triangle composed of two communicators coordinating and correcting their responses with a shared causal stimulus. This argument is important because it has a crucial advantage over the often used abductive argument for realism. My argument avoids unwarranted conclusions, whereas the abductive argument is “inflationary” because it reaches beyond the limits of evidence for its realist conclusion. To illustrate the problems of the abductive argument and motivate my Davidsonian approach, I take a brief look at the abductive argument for realism in Frederick Will’s work.

In this paper, we present a particular role for abductive reasoning in law by applying it in the context of an argumentation scheme for practical reasoning. We present a particular scheme, based on an established scheme for practical reasoning, that can be used to reason abductively about how an agent might have acted to reach a particular scenario, and the motivations for doing so. Plausibility here depends on a satisfactory explanation of why this particular agent followed these motivations in the particular situation. The scheme is given a formal grounding in terms of action-based alternating transition systems and we illustrate the approach with a running legal example. Keywords Argumentation schemes - Abductive reasoning - Practical reasoning.

Arguments by analogy are common in science, and in pseudoscience as well (especially "intelligent design theory"). A hierarchy of reasoning modes is presented, in which increasing confidence in the validity of inferences arises out of increasing lines of related evidence. The validity of all forms of argument are shown to be limited by the same thing: the logical limitations of argument by analogy. Therefore, there is (and can be) no ultimate certainty in any description or analysis of nature insofar as such descriptions or analyses are based on transduction, induction, deduction, abduction, and/or consilience (TIDAC). Generalizations formulated via simple analogy (transduction) are the weakest and generalizations formulated via consilience are the strongest. All we have (and can ever have) is relative degrees of confidence, based on repeated observations of similar objects and processes.