The measurement of sensory intensity has had a long history, attracting the attention of investigators from many disciplines including physiology, psychology, physics, mathematics, philosophy, and even chemistry. While there has been a continuing doubt by some that sensation has the properties necessary for measurement, experiments designed to obtain estimates of sensory intensity have found that a general rule applies: Equal stimulus ratios produce equal sensory ratios. Theories concerning the basis for this simple psychophysical rule are discussed, with emphasis given to (...) the physical correlate theory, which considers judgments of subjective magnitudes to be based upon estimates of physical dimensions that vary regularly with changes in degree of stimulation. For the most thoroughly investigated sensory scales, brightness and loudness, the physical correlate is considered to be distance. Our “tacit knowledge” of the sensory effects of changing distance plays an essential role in matching motor activities to environmental conditions and in ensuring accurate perceptual evaluations through brightness and loudness constancies. In psychophysical experiments, subjects apparently use this same tacit knowledge when required to estimate relative subjective magnitudes. The evidence related to the physical correlate theory is summarized, and it is concluded that, while under appropriate conditions we demonstrate considerable skill in evaluating environmental relationships, we are quite unable to estimate the neurophysiological nature or quantity of sensory response. A psychophysics devoted to studying conditions required for accuracy and conditions producing errors in the perception of environmental relationships would seem to be more valuable than one devoted to subjective magnitudes. (shrink)

J.L. Mackie insists that ordinary evaluative thought presents itself as a matter of sensitivity to aspects of the world. And this phenomenological thesis seems correct. When one or another variety of philosophical non-cognitivism claims to capture the truth about what the experience of value is like, or (in a familiar surrogate for phenomenology) about what we mean by our evaluative language, the claim is never based on careful attention to the lived character of evaluative thought or discourse. The idea is, (...) rather, that the very concept of the cognitive or factual rules out the possibility of an undiluted representation of how things are, enjoying, nevertheless, the internal relation to 'attitudes' or the will that would be needed to count as evaluative. On this view the phenomenology of value would involve a mere incoherence, if it were as Mackie says--a possibility that then tends (naturally enough) not to be so much as entertained. But, as Mackie sees, there is no satisfactory justification for supposing that the factual is, by definition, attitudinatively and motivationally neutral. This clears away the only obstacle to accepting his phenomenological claim; and the upshot is that non-cognitivism must offer to correct the phenomenology of value, rather than give an account of it. -/- In Machie's view the correction is called for. In this paper I want to suggest that he attributes an unmerited plausibility to this thesis, by giving a false picture of what one is committed to if one resists it. (shrink)

In his 1995 book Colour vision (New York: Routledge), Evan Thompson proposes a new approach to the ontology of color according to which it is tied to the ecological dispositions-affordances described by J.J. Gibson and his followers. Thompson claims that a relational account of color is necessary in order to avoid the problems that go along with the dispute between subjectivists and objectivists about color, but he claims that the received view of perception does not allow a satisfactory relational account (...) of color. Hence to avoid the problems of the subjectivist/objectivist dispute one must abandon the received view of perception. I describe an account which is similar to Thompson's, but which invokes instead the physical dispositional properties described by the received view. All of the distinguishing characteristics that Thompson claims separate his ecological dispositions from physical dispositions are in fact found in the physical dispositions appealed to by my proposed theory. Because my proposed theory is similar to subjectivism, Thompson's departure from the received view is not as radical as he claims. In a final section I describe the a posteriori manner in which a substantive departure from the received view must be carried out by describing an example of ecological experimentation. (shrink)

Constructive empiricism, the view introduced in The Scientific Image, is a view of science, an answer to the question "what is science?" Arthur Fine's and Paul Teller's contributions to this symposium challenge especially two key ideas required to formulate that view, namely the observable/unobservable and acceptance/belief distinctions. I wish to thank them not only for their insightful critique but also for the support they include. For they illuminate and counter some misunderstandings of Constructive Empiricism along the way. That leaves me (...) free to focus on those two main challenges. (shrink)

Different explanations of color vision favor different philosophical positions: Computational vision is more compatible with objectivism (the color is in the object), psychophysics and neurophysiology with subjectivism (the color is in the head). Comparative research suggests that an explanation of color must be both experientialist (unlike objectivism) and ecological (unlike subjectivism). Computational vision's emphasis on optimally prespecified features of the environment (i.e., distal properties, independent of the sensory-motor capacities of the animal) is unsatisfactory. Conceiving of visual perception instead as the (...) visual guidance of activity in an environment that is determined largely by that very activity suggests new directions for research. (shrink)

b>. Computational models of colour vision assume that the biological function of colour vision is to detect surface reflectance. Some philosophers invoke these models as a basis for 'externalism' about perceptual content (content is distal) and 'objectivism' about colour (colour is surface reflectance). In an earlier article (Thompson et al. 1992), I criticized the 'computational objectivist' position on the basis of comparative colour vision: There are fundmental differences among the colour vision of animals and these differences do not converge on (...) the detection of any single type of environmental property. David R. Hilbert (1992) has recently defended computational objectivism against my 'comparative argument;' his arguments are based on the externalist approach to perceptual content originally developed by Mohan Matthen (1988) and on the computationally inspired theory of the evolutionary basis for trichromacy developed by Roger N. Shepard (1990). The present article provides a reply to Hilbert with extensive criticism of both Matthen's and Shepard's theories. I argue that the biological function of colour vision is not to detect surface reflectance, but to provide a set of perceptual categories that can apply to objects in a stable way in a variety of conditions. Comparative research indicates that both the perceptual categories and the distal stimuli will differ according to the animal and its visual ecology; therefore externalism and objectivism must be rejected. (shrink)

Certain recent philosophical theories offer the prospect that zombies are possible. These theories argue that experiential contents, or qualia, are nonphysical properties. The arguments are based on the conceivability of alternate worlds in which physical laws and properties remain the same, but in which qualia either differ or are absent altogether. This article maintains that qualia are, on the contrary, physical properties in the world. It is shown how, under the burden of the a posteriori identification of qualia with physical (...) properties, a reasoned choice can be made between the two types of theories which ultimately favors materialism and rejects zombies. (shrink)

Sections R1 to R3 attempt to take the sting out of hostile commentaries. Sections R4 to R5 engage Berlin and Kay and the World Color Survey to correct the record. Section R6 begins the formulation of a new theory of colour as an engineering project with a technological developmental trajectory. It is recommended that the colour space be abandoned.

Martine Nida-Rümelin (1996) argues that color science indicates behaviorally undetectable spectrum inversion is possible and raises this possibility as an objection to functionalist accounts of visual states of color. I show that her argument does not rest solely on color science, but also on a philosophically controversial assumption, namely, that visual states of color supervene on physiological states. However, this assumption, on the part of philosophers or vision scientists, has the effect of simply ruling out certain versions of functionalism. While (...) Nida-Rümelin is quite right to search for empirical tests for claims about the nature of visual states, philosophical issues remain pivotal in determining the correctness of these claims. (shrink)

This volume consists of the first of the John Dewey Lectures delivered under the auspices of Columbia University's Philosophy Department as well as other essays by the author. Intended to clarify the meaning of the philosophical doctrines propounded by Professor Quine in 'Word and Objects', the essays included herein both support and expand those doctrines.

This article surveys work in epistemology since the mid-1980s. It focuses on contextualism about knowledge attributions, modest forms of foundationalism, and the internalism/externalism debate and its connections to the ethics of belief.

Although they may differ on the reason why, many philosophers hold that it is a priori that an object is red if and only if it is such as to look red to normal observers in normal conditions.

The relations among consciousness, brain, behavior, and scientific explanation are explored in the domain of color perception. Current scientific knowledge about color similarity, color composition, dimensional structure, unique colors, and color categories is used to assess Locke.

The paper proposes a way of bridging the gapbetween physical processes in the brain and the ''''felt''''aspect of sensory experience. The approach is based onthe idea that experience is not generated by brainprocesses themselves, but rather is constituted by theway these brain processes enable a particular form of''''give-and-take'''' between the perceiver and theenvironment. From this starting-point we are able tocharacterize the phenomenological differences betweenthe different sensory modalities in a more principledway than has been done in the past. We are also (...) ableto approach the issues of visual awareness andconsciousness in a satisfactory way. Finally weconsider a number of testable empirical consequences,one of which is the striking prediction of thephenomenon of ''''change blindness''''. (shrink)

Many current neurophysiological, psychophysical, and psychological approaches to vision rest on the idea that when we see, the brain produces an internal representation of the world. The activation of this internal representation is assumed to give rise to the experience of seeing. The problem with this kind of approach is that it leaves unexplained how the existence of such a detailed internal representation might produce visual consciousness. An alternative proposal is made here. We propose that seeing is a way of (...) acting. It is a particular way of exploring the environment. Activity in internal representations does not generate the experience of seeing. The out- side world serves as its own, external, representation. The experience of seeing occurs when the organism masters what we call the gov- erning laws of sensorimotor contingency. The advantage of this approach is that it provides a natural and principled way of accounting for visual consciousness, and for the differences in the perceived quality of sensory experience in the different sensory modalities. Sev- eral lines of empirical evidence are brought forward in support of the theory, in particular: evidence from experiments in sensorimotor adaptation, visual “filling in,” visual stability despite eye movements, change blindness, sensory substitution, and color perception. (shrink)

Susan Hurley has attacked the ''Duplication Assumption'', the assumption thatcreatures with exactly the same internal states could function exactly alike inenvironments that are systematically distorted. She argues that the dynamicalinterdependence of action and perception is highly problematic for the DuplicationAssumption when it involves spatial states and capacities, whereas no such problemsarise when it involves color states and capacities. I will try to establish that theDuplication Assumption makes even less sense for lightness than for some ofthe spatial cases. This is due (...) not only to motor factors, but to the basic physicalasymmetry between black and white. I then argue that the case can be extendedfrom lightness perception to hue perception. Overall, the aims of this paper are:(1) to extend Susan Hurley''s critique of the Duplication Assumption; (2) to argueagainst highly constrained versions of Inverted Spectrum arguments; (3) to proposea broader conception of the vehicle for color perception. (shrink)

The world as we experience it is full of colour. This book defends the radical thesis that no physical object has any of the colours we experience it as having. The author provides a unified account of colour that shows why we experience the illusion and why the illusion is not to be dispelled but welcomed. He develops a pluralist framework of colour-concepts in which other, more sophisticated concepts of colour are introduced to supplement the simple concept that is presupposed (...) in our ordinary colour experience. The discussion draws on philosophical and scientific literature, both historical and modern, but it is not technical, and will appeal to a broad range of philosophers, cognitive scientists and historians of science. (shrink)

What is color? What is color vision? Most philosophers answer by reference to humans: to human color qualia, or to the environmental properties or "quality spaces" perceived by humans. It is argued, with reference to empirical findings concerning comparative color vision and the evolution of color vision, that all such attempts are mistaken. An adequate definition of color vision must eschew reference to its outputs in the human cognition and refer only to inputs: color vision consists in the use of (...) wavelength discrimination in the construction of visual representations. A color quality is one that is generated from such processing. (shrink)

Perceptions "present" objects as red, as round, etc.-- in general as possessing some property. This is the "perceptual content" of the title, And the article attempts to answer the following question: what is a materialistically adequate basis for assigning content to what are, after all, neurophysiological states of biological organisms? The thesis is that a state is a perception that presents its object as "F" if the "biological function" of the state is to detect the presence of objects that are (...) "F". The theory contrasts with causal/informational theories, and with internalist theories, for example those which assign content on the basis of introspected feel. Its advantages are that it permits perceptual error while at the same time allowing content to be expressed in terms of external properties. The argument of the paper is illustrated throughout by examples from biology and computational psychology. (shrink)

How do rational minds make contact with the world? The empiricist tradition sees a gap between mind and world, and takes sensory experience, fallible as it is, to provide our only bridge across that gap. In its crudest form, for example, the traditional idea is that our minds consult an inner realm of sensory experience, which provides us with evidence about the nature of external reality. Notoriously, however, it turns out to be far from clear that there is any viable (...) conception of experience which allows it to do the job. The original problem is to show that thought is rationally constrained by external reality. If sensory experience is to provide the solution--in particular, if it is to provide the answer to sceptical challenges--it must therefore meet two criteria. First, it must itself be `receptive'--i.e., appropriately constrained by external reality. Second, it must be the kind of thing that can enter into a logical or rational relationship with belief--it must already be `conceptual,' in other words. In arguing against the idea that anything could serve both roles, Wilfred Sellars termed this conception of experience "the Myth of the Given.". (shrink)

There are serious reasons for accepting each of these propositions individually but there are apparently insurmountable difficulties with accepting all three of them simultaneously if we assume that color is a single property. 1) and 2) together seem to imply that there is some property which all organisms with color vision can see and 3) seems to imply that there can be no such property. If these implications really are valid then one or more of these propositions will have to (...) be rejected in spite of whatever reasons can be given for their apparent acceptability. Before going on to discuss possible resolutions of this apparent contradiction it is worth pointing out there our three propositions are not all of a kind. Proposition 1) is a metaphysical thesis about the ontological status of color and proposition 3) is an empirical thesis about what properties organisms with color vision are capable of detecting. If you accept 1) then 2) will appear to verge on the trivial, but if 1) is denied then the status of 2) will appear more problematic. In what follows I will have more to say about why we either should or should not accept all three of these propositions. (shrink)

Why a hermeneutical philosophy of the natural sciences? It is necessary to address the philosophic crisis of realism vs relativism in the natural sciences. This crisis is seen as a part of the cultural crisis that Husserl and Heidegger identified and attributed to the hegemonic role of theoretical and calculative thought in Western societies. The role of theory is addressed using the hermeneutical circle to probe the origin of theoretic meaning in scientific cultural praxes. This is studied in Galileo's discovery (...) of the phases of Venus; the practice of measurement; the different theories and practices of space perception; the historicality and temporality of scientific research communities which ground paradigm change; and the process of discovery. The paper draws particularly from the work of Heidegger. Though envisaging all science and scholarship, the highlighted theme is research in the natural sciences. (shrink)