General philosophy claims to be the critical subject which lays down for all of us what we may be allowed to think, and yet it has played no part whatever in the great revolutions of human thought of the present century—those connected with relativity and the quantum theory. It might have been expected that the scientists would have been constantly consulting the philosophers as to the legitimacy of their various speculations, but nothing of the kind has happened. Since no one (...) can dispense with some sort of meta-physic, each scientist has made one for himself, and no doubt they contain many crudities, but it would seem that a deep interest in metaphysic is a disadvantage rather than an advantage to the physicist—at least I have the impression that those of my friends who are most inclined to speculate on the ultimate things appear to be the ones whose scientific work is most hampered by doing so. Now I propose to risk a similar indiscretion. I want to embody in it the practical philosophy of a physicist, and I do not mean it as an attack on the pure philosophers, who are very reasonable people, only chargeable with the minor offence of not having made me want to read their books! (shrink)

Deep brain stimulation of the subthalamic nucleus is a clinically effective tool for treating medically refractory Parkinson’s disease, but its neural mechanisms remain debated. Previous work has demonstrated that STN DBS results in evoked potentials in the primary motor cortex, suggesting that modulation of cortical physiology may be involved in its therapeutic effects. Due to technical challenges presented by high-amplitude DBS artifacts, these EPs are often measured in response to low-frequency stimulation, which is generally ineffective at PD symptom management. This (...) study aims to characterize STN-to-cortex EPs seen during clinically relevant high-frequency STN DBS for PD. Intraoperatively, we applied STN DBS to 6 PD patients while recording electrocorticography from an electrode strip over the ipsilateral central sulcus. Using recently published techniques, we removed large stimulation artifacts to enable quantification of STN-to-cortex EPs. Two cortical EPs were observed – one synchronized with DBS onset and persisting during ongoing stimulation, and one immediately following DBS offset, here termed the “start” and the “end” EPs respectively. The start EP is, to our knowledge, the first long-latency cortical EP reported during ongoing high-frequency DBS. The start and end EPs differ in magnitude and latency, and the end, but not the start, EP magnitude has a significant relationship to ongoing high gamma power during the EP. These contrasts may suggest mechanistic or circuit differences in EP production during the two time periods. This represents a potential framework for relating DBS clinical efficacy to the effects of a variety of stimulation parameters on EPs. (shrink)

Word recognition is the Petri dish of the cognitive sciences. The processes hypothesized to govern naming, identifying and evaluating words have shaped this field since its origin in the 1970s. Techniques to measure lexical processing are not just the back-bone of the typical experimental psychology laboratory, but are now routinely used by cognitive neuroscientists to study brain processing and increasingly by social and clinical psychologists (Eder, Hommel, and De Houwer 2007). Models developed to explain lexical processing have also aspired to (...) be statements about the nature of human cognition (e.g., connectionist models, Plaut, McClelland, Seidenberg, and Patterson 1996). Words were convenient objects to study for cognitive psychologists because they are welldefined and their nature as alphabetic strings was a good fit to analysis with the computer programming languages of the 1970s and 1980s which excelled at string manipulation. But are words actually the privileged unit of mental representation and processing that all of this scientific attention makes them out to be? Like a growing number of other language researchers, our answer is no (see, e.g., (Bybee and Hopper 2001; Wray 2002). We propose that the mental representations for lexical structures form a continuum, from word combinations which have fossilized into single units (nightclub) to those that both exist as independent units and yet have bonds, varying in tightness, with the words with which they frequently co-occur (Harris 1998). The first line of support for this view is the simple observation that fluent speakers easily recognize the familiarity and cohesive quality of word combinations in their language. Examples in English include common noun compounds (last year, brand new), verb phrases (cut down, get a hold of, faced with) and other multi-word expressions such as common sayings and references to cultural concepts (saved by the bell, speed of light; Jackendoff 1995).. (shrink)

Many human cultural traits become increasingly beneficial as they are repeatedly transmitted, thanks to an accumulation of modifications made by successive generations. But how do later generations typically avoid modifications which revert traits to less beneficial forms already sampled and rejected by earlier generations? And how can later generations do so without direct exposure to their predecessors' behavior? One possibility is that learners are sensitive to cues of non‐random production in others' behavior, and that particular variants (e.g., those containing structural (...) regularities unlikely to occur spontaneously) have been produced deliberately and with some effort. If this non‐random behavior is attributed to an informed strategy, then the learner may infer that apparent avoidance of certain possibilities indicates that these have already been sampled and rejected. This could potentially prevent performance plateaus resulting from learners modifying inherited behaviors randomly. We test this hypothesis in four experiments in which participants, either individually or in interacting dyads, attempt to locate rewards in a search grid, guided by partial information about another individual's experience of the task. We find that in some contexts, valid inferences about another's behavior can be made from partial information, and these inferences can be used in a way which facilitates trait adaptation. However, the benefit of these inferences appears to be limited, and in many contexts—including some which have the potential to make inferring the experience of another individual easier—there appears to be no benefit at all. We suggest that inferring previous behavior from partial social information plays a minimal role in the adaptation of cultural traits. (shrink)

Wallace's contributions to biological thought tend to be overlooked or overly praised, neither of which produces a satisfactory assessment. Examples of the latter tendency are the recent expositions by Brackman and Brooks; although both books contain much worthwhile material, both are flawed. At critical points their theories fail to measure up, Brackman's because of his misinterpretations of events in the month of June 1858, and Brooks's Darwin's September 5 letter to Gray could, and probably did, represent an ordering of (...) his ideas in response to a felt challenge.A fruitful way to characterize the relationship between Darwin and Wallace may be found in terms of game theory. Most scholars look upon the relationship as a zero-sum game, with a winner and a loser, the matter of priority being considered as a “single event.” Another approach would be to look upon it as a non-zero-sum game with each man influencing the other. In this case, the productivity of one is stimulated by the contributions of the other, resulting in a net gain in knowledge overall, and both men become winners, or codiscoverers. This approach is possible if Wallace's contributions to the theory of evolution by means of natural selection are recognized. (shrink)

It is often claimed that one of Darwin''s chief accomplishments was to provide biology with a non-teleological explanation of adaptation. A number of Darwin''s closest associates, however, and Darwin himself, did not see it that way. In order to assess whether Darwin''s version of evolutionary theory does or does not employ teleological explanation, two of his botanical studies are examined. The result of this examination is that Darwin sees selection explanations of adaptations as teleological explanations. (...) The confusion in the nineteenth century about Darwin''s attitude to teleology is argued to be a result of Darwin''s teleological explanations not conforming to either of the dominant philosophical justifications of teleology at that time. Darwin''s explanatory practices conform well, however, to recent defenses of the teleological character of selection explanations. (shrink)

This paper examines Charles Darwin’s idea that language-use and humanity’s unique cognitive abilities reinforced each other’s evolutionary emergence—an idea Darwin sketched in his early notebooks, set forth in his Descent of man , and qualified in Descent’s second edition. Darwin understood this coevolution process in essentially Lockean terms, based on John Locke’s hints about the way language shapes thinking itself. Ironically, the linguist Friedrich Max Müller attacked Darwin’s human descent theory by invoking a similar thesis, the (...) German romantic notion of an identity between language and thought. Although Darwin avoided outright contradiction, when he came to defend himself against Müller’s attacks, he undercut some of his own argumentation in favor of the coevolution idea. That is, he found it difficult to counter Müller’s argument while also making a case for coevolution. Darwin’s efforts in this area were further complicated by British and American writers who held a naturalistic view of speech origins yet still taught that language had been invented by fully evolved homo sapiens, thus denying coevolution. (shrink)

This essay traces the interlinked origins of two concepts found in Charles Darwin's writings: "unconscious selection," and sexual selection as applied to humanity's anatomical race distinctions. Unconscious selection constituted a significant elaboration of Darwin's artificial selection analogy. As originally conceived in his theoretical notebooks, that analogy had focused exclusively on what Darwin later would call "methodical selection," the calculated production of desired changes in domestic breeds. By contrast, unconscious selection produced its results unintentionally and at a much (...) slower pace. Inspiration for this concept likely came from Darwin's early reading of works on both animal breeding and physical ethnology. Texts in these fields described the slow and unplanned divergence of anatomical types, whether animal or human, under the guidance of contrasting ideals of physical perfection. These readings, it is argued, also led Darwin to his theory of sexual selection as applied to race, a theme he discussed mainly in his book The Descent of Man. There Darwin described how the racial version of sexual selection operated on the same principle as unconscious selection. He thereby effectively reunited these kindred concepts. (shrink)

This essay outlines one aspect of a larger collaboration with John Beatty and Alan Love.2 The project’s focus is philosophical, but for reasons that will become clear momentarily, the method of approach is historical. All three of us share the conviction that philosophical issues concerning the foundations of the sciences are often illuminated by investigating their history. It is my hope that this paper both provides support for that thesis, and illustrates it. The focal philosophical issue can be stated in (...) the form of a puzzle about contemporary discussions of the conceptual foundations of evolutionary theory. The role of the concepts of “chance” and “randomness” in that theory is a significant part of .. (shrink)

This paper examines the way Charles Darwin applied his domestic breeding analogy to the practical workings of species evolution: that application, it is argued, centered on Darwin's distinction between methodical and unconscious selection. Methodical selection, which entailed pairing particular individuals for mating purposes, represented conditions of strict geographic isolation, obviously useful for species multiplication (speciation). By contrast, unconscious selection represented an open landmass with a large breeding population. Yet Darwin held that this latter scenario, which often would (...) include multiple ecological subdistricts and thus partial isolation, was better suited for speciation than were isolated conditions. At the same time, many passages in Darwin's writings that apparently portrayed phyletic evolution exclusively (these including references to unconscious selection), actually applied to speciation as well, for phyletic change in a single district could constitute a local manifestation of a larger common-descent pattern. This generic use of "phyletic" change was reflected in Darwin's deployment of the unconscious selection analogy in his published writings as well as in his dispute with Moritz Wagner over the necessity of geographic isolation for speciation. We can thus understand Darwin's otherwise puzzling declaration in The Origin of Species that unconscious selection was 'more important' than the methodical approach. (shrink)

This book offers a thorough reanalysis of Charles Darwin's Origin of Species, which for many people represents the work that alone gave rise to evolutionism. Of course, scholars today know better than that. Yet, few resist the temptation of turning to the Origin in order to support it or reject it in light of their own work. Apparently, Darwin fills the mythical role of a founding figure that must either be invoked or repudiated. The book is an invitation (...) to move beyond what is currently expected of Darwin's magnum opus. Once the rhetorical varnish of Darwin's discourses is removed, one discovers a work of remarkably indecisive conclusions. The book comprises two main theses: The Origin of Species never remotely achieved the theoretical unity to which it is often credited. Rather, Darwin was overwhelmed by a host of phenomena that could not fit into his narrow conceptual framework. In the Origin of Species, Darwin failed at completing the full conversion to evolutionism. Carrying many ill-designed intellectual tools of the 17th and 18th centuries, Darwin merely promoted a special brand of evolutionism, one that prevented him from taking the decisive steps toward an open and modern evolutionism. It makes an interesting read for biologists, historians and philosophers alike. (shrink)

A necessary condition for having a revolution named after you is that you are an innovator in your field. I argue that if Charles Darwin meets this condition, it is as a philosopher and methodologist. In 1991, I made the case for Darwin's innovative use of "thought experiment" in the "Origin." Here I place this innovative practice in the context of Darwin's methodological commitments, trace its origins back into Darwin's notebooks, and pursue Darwin's suggestion that (...) it owes its inspiration to Charles Lyell. (shrink)

In the second chapter of The descent of man , Charles Darwin interrupted his discussion of the evolutionary origins of language to describe ten ways in which the formation of languages and of biological species were ‘curiously’ similar. I argue that these comparisons served mainly as analogies in which linguistic processes stood for aspects of biological evolution. Darwin used these analogies to recapitulate themes from On the origin of species , including common descent, genealogical classification, the struggle for (...) existence, and natural selection, among others. Skeptical of this interpretation, Gregory Radick sees the naturalistic account of language formation in the Descent comparisons as reinforcing Darwin’s idea that languages and the races of mankind have both undergone progressive development. Yet the details of Darwin’s language–species comparisons, as well as the polemical context in which they appear, show that they were not aimed at so limited a function. Rather, they addressed issues related to species transmutation in general. (shrink)

The analogy Darwin drew between artificial and natural selection in "On the Origin of Species" has a detailed structure that has not been appreciated. In Darwin’s analogy, the kind of artificial selection called Methodical selection is analogous to the principle of divergence in nature, and the kind of artificial selection called Unconscious selection is analogous to the principle of extinction in nature. This paper argues that it is the analogy between these two different principles familiar from his studies (...) of artificial selection and the two different principles he claims are operative in nature that provides the main structure and force of the analogy he uses to make his case for the power of natural selection to produce new species. Darwin’s statements explicitly distinguishing between these two kinds of principles at work in nature occur prominently in the text of the Origin. The paper also shows that a recent revisionist claim that Darwin did not appeal to the efficacy of artificial selection is mistaken. (shrink)

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Summary In The Origin of Species, Charles Darwin famously accounted for the lack of fossil evidence in support of species evolution on the grounds that the fossil record is naturally incomplete. This essay examines a similar argument that Darwin applied to his analogy between natural and artificial selection: the scarcity of data about the historical backgrounds of domestic breeds was the natural by-product of an extremely gradual change process. The point was to enhance the ability of the artificial (...) selection analogy to suggest that nature's species had undergone a similar transformation. Darwin did not depend on this negative inference alone, however, for in his writings he included whatever information he could find about the actual histories of particular breeds. A comparison with Darwin's treatment of the fossil record suggests the reasonableness of this combined use of opposite kinds of evidence to establish a single point. The comparison also suggests the unique qualities of negative inference as applied to the breeding analogy. (shrink)