Online research in philosophy

The purpose of this paper is to clarify Prajñākaragupta’s view of mental perception ( mānasapratyakṣa ), with special emphasis on the relationship between mental perception and self-awareness. Dignāga, in his PS 1.6ab, says: “mental [perception] ( mānasa ) is [of two kinds:] a cognition of an [external] object and awareness of one’s own mental states such as passion.” According to his commentator Jinendrabuddhi, a cognition of an external object and awareness of an internal object such as passion are here equally called ‘mental perception’ in that neither depends on any of the five external sense organs. Dharmakīrti, on the other hand, considers mental perception to be a cognition which arises after sensory perception, and does not call self-awareness ‘mental perception’. According to Prajñākaragupta, mental perception is the cognition which determines an object as ‘this’ ( idam iti jñānam ). Unlike Dharmakīrti, he holds that the mental perception follows not only after the sensory perception of an external object, but also after the awareness of an internal object. The self-awareness which Dignāga calls ‘mental perception’ is for Prajñākaragupta the cognition which determines as ‘this’ an internal object, or an object which consists in a cognition; it is to be differentiated from the cognition which cognizes cognition itself, that is, self-awareness in its original sense.

Both imagery and imagination play an important part in our mental lives. This article, which has three main sections, discusses both of these phenomena, and the connection between them. The first part discusses mental images and, in particular, the dispute about their representational nature that has become known as the _imagery debate_ . The second part turns to the faculty of the imagination, discussing the long philosophical tradition linking mental imagery and the imagination—a tradition that came under attack in the early part of the twentieth century with the rise of behaviorism. Finally, the third part of this article examines modal epistemology, where the imagination has been thought to serve an important philosophical function, namely, as a guide to possibility.

I present a view of conscious perception that supposes a processual unity between the activity in the brain and the perceived event in the external world. I use the rainbow to provide a first example, and subsequently extend the same rationale to more complex examples such as perception of objects, faces and movements. I use a process-based approach as an explanation of ordinary perception and other variants, such as illusions, memory, dreams and mental imagery. This approach provides new insights into the problem of conscious representation and phenomenal consciousness. It is a form of anti- cranialism different from but related to other kinds of externalism.

What is difficult to imagine is also surprising to perceive. This indicates that active visual imagery is an integral part of active visual perception. Erroneous mental transformations provide clues to prior assumptions in visual imagery, just as visual illusions provide clues to perceptual assumptions. Visual imagery and perception share generic assumptions about invariants in images of rigid objects.

This paper explores the question whether an adequate account of the facts about imagination and mental imagery must construe mental images as objects. Much of the paper is a study of Alastair Hannay's defense of an affirmative answer in his wide?ranging study, Mental Images ? A Defence. The paper first sets out and evaluates Hannay's case. The second part develops an alternative account of mental images, including non?visual images, which Hannay does not treat in detail. The alternative account is analogous to the adverbial theory of perception; and it is suggested how this account, without construing mental images as objects, might accommodate the data from which Hannay argues for their objecthood.

Can theories of mental imagery, conscious mental contents, developed within cognitive science throw light on the obscure (but culturally very significant) concept of imagination? Three extant views of mental imagery are considered: quasi-pictorial, description, and perceptual activity theories. The first two face serious theoretical and empirical difficulties. The third is (for historically contingent reasons) little known, theoretically underdeveloped, and empirically untried, but has real explanatory potential. It rejects the "traditional" symbolic computational view of mental contents, but is compatible with recent *situated cognition* and *active vision* approaches in robotics. This theory is developed and elucidated. Three related key aspects of imagination (non-discursiveness, creativity, and *seeing as*) raise difficulties for the other theories. Perceptual activity theory presents imagery as non-discursive and relates it closely to *seeing as*. It is thus well placed to be the basis for a general theory of imagination and its role in creative thought.

A comprehensive theory of the structure and cognitive function of the human imagination, and its relationship to perceptual experience, is developed, largely through a critique of the account propounded in Colin McGinn's Mindsight. McGinn eschews the highly deflationary (and unilluminating) views of imagination common amongst analytical philosophers, but fails to develop his own account satisfactorily because (owing to a scientifically outmoded understanding of visual perception) he draws an excessively sharp, qualitative distinction between imagination and perception (following Wittgenstein, Sartre, and others), and because of his fatally flawed, empirically ungrounded conception of hallucination. In fact, however, an understanding of perception informed by modern visual science will enable us to unify our accounts of perception, mental imagery, dreaming, hallucination, creativity, and other aspects of imagination within a single coherent theoretical framework.

A comprehensive theory of the structure and cognitive function of the human imagination, and its relationship to perceptual experience, is developed, largely through a critique of the account propounded in Colin McGinn's Mindsight. McGinn eschews the highly deflationary (and unilluminating) views of imagination common amongst analytical philosophers, but fails to develop his own account satisfactorily because (owing to a scientifically outmoded understanding of visual perception) he draws an excessively sharp, qualitative distinction between imagination and perception (following Wittgenstein, Sartre, and others), and because of his fatally flawed, empirically ungrounded conception of hallucination. In fact, however, an understanding of perception informed by modern visual science will enable us to unify our accounts of perception, mental imagery, dreaming, hallucination, creativity, and other aspects of imagination within a single coherent theoretical framework.

A theory of perception must be capable of explaining the full range of conscious perception, including amodal perception. In amodal perception we perceive the world to contain physical features that are not directly detectable by the sensory receptors. According to the active-externalist theory of perception, amodal perception depends on active engagement with perceptual objects. This paper focuses on amodal visual perception and presents a counter-example to the idea that active-externalism can account for amodal perception. The counterexample involves the experience of so-called ‘impossible objects’, objects experienced in perceptual character as having geometrical properties that no physically real object can have.

The problem of amodal perception is the problem of how we represent features of perceived objects that are occluded or otherwise hidden from us. Bence Nanay (2010) has recently proposed that we amodally perceive an object's occluded features by imaginatively projecting them into the relevant regions of visual egocentric space. In this paper, I argue that amodal perception is not a single, unitary capacity. Drawing appropriate distinctions reveals amodal perception to be characterized not only by mental imagery, as Nanay suggests, but also by genuinely visual representations as well as beliefs. I conclude with some brief remarks on the role of object-directed bodily action in conferring a sense of unseen presence on an object's occluded features.