The role of conventions in the formulation of Thomas Reid’s theory of the geometry of vision, which he calls the “geometry of visibles”, is the subject of this investigation. In particular, we will examine the work of N. Daniels and R. Angell who have alleged that, respectively, Reid’s “geometry of visibles” and the geometry of the visual field are non-Euclidean. As will be demonstrated, however, the construction of any geometry of vision is subject to a choice of conventions regarding the (...) construction and assignment of its various properties, especially metric properties, and this fact undermines the claim for a unique non-Euclidean status for the geometry of vision. Finally, a suggestion is offered for trying to reconcile Reid’s direct realist theory of perception with his geometry of visibles. (shrink)

Thomas Reid’s epistemological ambitions are decisively at the center of his work. However, if we take such ambitions to be the whole story, we are apt to overlook the theory of mind that Reid develops and deploys against the theory of ideas. Reid’s philosophy of mind is sophisticated and strikingly contemporary, and has, until recently, been lost in the shadow of his other philosophical accomplishments. Here I survey some aspects of Reid’s theory of mind that I find most interesting. I (...) examine whether Reid is a mysterian about the mind, whether Reid has a direct realist theory of perception, and whether Reid has a higher-order, or “inner-sense,” view of consciousness. Along the way I will mention portions of the secondary literature that examine these aspects and point out whether and to what degree I part ways with the interpretations present in the literature. (shrink)

Two significant aspects of Thomas Reid's thought seem to be irreconcilable with one another. On the one hand, Reid constantly refers to the substantive benefits which human knowledge receives from the Christian revelation. On the other hand, he does not justify philosophical or scientific beliefs by way of appeal to God. In this essay, I argue that a closer inspection of both Reid's philosophical reflection and scientific investigations shows that the two aspects just mentioned are compatible with one another. In (...) short, although an influence on rational investigation is somehow exerted by divine revelation, this does not limit the autonomy of reason, which is actually stimulated and promoted precisely because of a religiously rooted confidence in our rational faculties. (shrink)

There is a problem about the compatibility of Reid's commitment to both a sign theory of sensations and also direct realism. I show that Reid is committed to three different senses of the claim that mind independent bodies and their qualities are among the immediate objects of perception, and I then argue that Reid's sign theory conflicts with one of these. I conclude by advocating one proposal for reconciling Reid's claims, deferring a thorough development and defence of the proposal to (...) another paper. (shrink)

The controversy over the interpretative issue—is Thomas Reid a perceptual direct realist?—has recently had channelled into it a host of imaginative ideas about what direct perception truly means. Paradoxically enough, it is the apparent contradiction at the heart of his view of perception which keeps teasing us to review our concepts: time and again, Reid stresses that the very idea of any mental intermediaries implies scepticism, yet, nevertheless insists that sensations are signs of objects. But if sensory signs are not (...) mental intermediaries, what are they? Hasn't Reid merely swapped the common ‘sensation’ for the notorious ‘idea’, ending up with indirect realism?1 Current imaginative strategies answer negatively: Reid's sensory sign does not contradict direct perception, and those who think otherwise merely fail to understand what it means. (shrink)

I suggest two main ways of interpreting Reid's analysis of the perception of the quality of hardness: Reid endorses two distinct concepts of hardness. The distinction between the two lies in a profoundly different relation between the sensation of hardness and the concept of hardness in each of them. The first concept, which I term as a “sensation-laden concept”, is “the quality that arises in us the sensation of hardness.” The second concept, which I call a “non-sensational concept”, is “the (...) cohesion of the parts of the body with more or less force.” Reid is thinking like a developmental psychologist and postulates what I consider as a gradual development from one concept to the other according to which the initial sensation-laden concept of hardness, which we form during our early childhood, gradually develops into a mature non-sensational concept of hardness. (shrink)

In his 'Inquiry', Reid claims, against Berkeley, that there is a science of the perspectival shapes of objects ('visible figures'): they are geometrically equivalent to shapes projected onto the surfaces of spheres. This claim should be understood as asserting that for every theorem regarding visible figures there is a corresponding theorem regarding spherical projections; the proof of the theorem regarding spherical projections can be used to construct a proof of the theorem regarding visible figures, and vice versa. I reconstruct Reid's (...) argument for this claim, and expose its mathematical underpinnings: it is successful, and depends on no empirical assumptions to which he was not entitled about the workings of the human eye. I also argue that, although Reid may or may not have been aware of it, the geometry of spherical projections is not the only geometry of visible figure. (shrink)

Thomas Reid claims to have learned of Idomenians, “an order of beings” in “sublunary regions” whose visual system is very much like ours except that they could detect only the direction of rays reaching their eyes, not the distance of origin. The properties of Idomenian vision are here examined in the light of the physiological optics of Reid’s time and of the scientific developments that have since augmented our knowledge of the discipline.

This essay argues that Humean impressions are triggers of associative processes, which enable us to form stable patterns of thought that co-vary with our experiences of the world. It will thus challenge the importance of the Copy Principle by claiming that it is the regularity with which certain kinds of sensory inputs motivate certain sets of complex ideas that matters for the discrimination of ideas. This reading is conducive to Hume’s account of perception, because it avoids the impoverishment of conceptual (...) resources so typical for empiricist theories of meaning and explains why ideas should be based on impressions, although impressions cannot be known to mirror matters of fact. Dieser Aufsatz argumentiert dafür, dass humesche Eindrücke Auslöser von assoziativen Prozessen sind, welche es uns ermöglichen, stabile Denkmuster zu bilden, die mit unseren Erfahrungen der Welt kovariant sind. Der Aufsatz stellt somit die Wichtigkeit des Kopien-Prinzips in Frage, nämlich dadurch, dass behauptet wird, für die Unterscheidung der Ideen sei die Regelmäßigkeit maßgeblich, mit der gewisse Arten von sensorischen Eingaben gewisse Mengen von komplexen Ideen motivieren. Diese Lesart trägt zu einem Verständnis von Humes Auffassung der Wahrnehmung bei, da sie die Verarmung der begrifflichen Mittel, die für empiristische Theorien der Bedeutung so typisch ist, vermeidet und erklärt, warum Ideen auf Eindrücken basieren sollten, obwohl Eindrücke nicht als Abbildungen von Tatsachen erkannt werden können. (shrink)

Abstract: In this paper I consider recent attempts to establish that the geometry of visual experience is a spherical geometry. These attempts, offered by Gideon Yaffe, James van Cleve and Gordon Belot, follow Thomas Reid in arguing for an equivalency of a geometry of ‘visibles’ and spherical geometry. I argue that although the proposed equivalency is successfully established by the strongest form of the argument, this does not warrant any conclusion about the geometry of visual experience. I argue, firstly, that (...) the resistance of this contemporary argument to empirical considerations counts against its plausibility. Moreover, I argue that the contemporary approach provides no compelling reason for supposing that the geometry offered as the geometry of ‘visibles’ is the correct geometrical description of visual experience. (shrink)

Thomas Reid's Geometry of Visibles, according to which the geometrical properties of an object's perspectival appearance equal the geometrical properties of its projection on the inside of a sphere with the eye in its centre allows for two different interpretations. It may (1) be understood as a theory about phenomenal visual space – i.e. an account of how things appear to human observers from a certain point of view – or it may (2) be seen as a mathematical model of (...) viewpoint-relative but mind-independent relational properties of objects. This paper makes a systematic and a historical claim. I shall argue, first, that given certain features of the human visual system phenomenal visual space differs in several aspects from Reidean visual space. Secondly, I suggest that, since Reid was aware of some of these empirical facts, we should interpret Reid as endorsing the second interpretation of the Geometry of Visibles. (shrink)

I survey some important semantical and axiomatic theories of self-referential truth. Kripke's fixed-point theory, the revision theory of truth and appraoches involving fuzzy logic are the main examples of semantical theories. I look at axiomatic theories devised by Cantini, Feferman, Freidman and Sheard. Finally some applications of the theory of self-referential truth are considered.

Two theses appear to be central to Reid’s view of the visual field. By sight, we do not originally perceive depth or linear distance from the eye. By sight, we originally perceive the position that points on the surface of objects have with regard to the centre of the eye. In different terms, by sight, we originally perceive the compass direction and degree of elevation of points on the surface of objects with reference to the centre of the eye. I (...) consider various problems about distance perception and perception of position with regard to the centre of the eye raised by Reid’s texts. These questions are relevant to Reid’s description of the geometry of visibles as the “intrinsic” geometry of the surface of the sphere. (shrink)

Drawing on work done by Helmholtz, I argue that Reid was in no position to infer that objects appear as if projected on the inner surface of a sphere, or that they have the geometric properties of such projections even though they do not look concave towards the eye. A careful consideration of the phenomena of visual experience, as further illuminated by the practice of visual artists, should have led him to conclude that the sides of visible appearances either look (...) straight, in which case their angles appear to approximate Euclidean measures, or their angles do not appear to approximate Euclidean measures for straight line figures, in which case their sides do not look straight. (shrink)