Non-visual consciousness and visual images in blindsight

In a recent response paper to Brogaard (2011a), Morten Overgaard and Thor Grünbaum argue that my case for the claim that blindsight subjects are not visually conscious of the stimuli they correctly identify rests on a mistaken necessary criterion for determining whether a conscious experience is visual or non-visual. Here I elaborate on the earlier argument while conceding that the question of whether blindsight subjects are visually conscious of the visual stimuli they correctly identify largely is an empirical question. I conclude by sketching a method for testing whether blindsight subjects have visual consciousness of stimuli presented to them in their blind field.     

Implicit biases in visually guided action

For almost half a century dual-stream advocates have vigorously defended the view that there are two functionally specialized cortical streams of visual processing originating in the primary visual cortex: a ventral, perception-related ‘conscious’ stream and a dorsal, action-related ‘unconscious’ stream. They furthermore maintain that the perceptual and memory systems in the ventral stream are relatively shielded from the action system in the dorsal stream. In recent years, this view has come under scrutiny. Evidence points to two overlapping action pathways: a dorso-dorsal pathway that calculates features of the object to be acted on, and a ventro-dorsal pathway that transmits stored information about skilled object use from the ventral stream to the dorso-dorsal pathway. This evidence suggests that stored information may exert significantly more influence on visually guided action than hitherto assumed. I argue that this, in turn, supports the notion of skilled automatic action that is nonetheless agential. My focus here will be on actions influenced by implicit biases (stereotypes/prejudices). Action that is biased in this way, I argue, is in an important sense intentional and agential.

     

Are there unconscious perceptual processes?

Blindsight and vision for action seem to be exemplars of unconscious visual processes. However, researchers have recently argued that blindsight is not really a kind of unconscious vision but is rather severely degraded conscious vision. Morten Overgaard and colleagues have recently developed new methods for measuring the visibility of visual stimuli. Studies using these methods show that reported clarity of visual stimuli correlates with accuracy in both normal individuals and blindsight patients. Vision for action has also come under scrutiny. Recent findings seem to show that information processed by the dorsal stream for online action contributes to visual awareness. Some interpret these results as showing that some dorsal stream processes are conscious visual processes (e.g., Gallese, 2007; Jacob & Jeannerod, 2003). The aim of this paper is to provide new support for the more traditional view that blindsight and vision for action are genuinely unconscious perceptual processes. I argue that individuals with blindsight do not have access to the kind of purely qualitative color and size information which normal individuals do. So, even though people with blindsight have a kind of cognitive consciousness, visual information processing in blindsight patients is not associated with a distinctly visual phenomenology. I argue further that while dorsal stream processing seems to contribute to visual awareness, only information processed by the early dorsal stream (V1, V2, and V3) is broadcast to working memory. Information processed by later parts of the dorsal stream (the parietal lobe) never reaches working memory and hence does not correlate with phenomenal awareness. I conclude that both blindsight and vision for action are genuinely unconscious visual processes.     

Moral Relativism and Moral Expressivism

Though moral relativism has had its supporters over the years, it is not a dominant position in philosophy. I will argue here, though, that the view is an attractive position. It evades some hardcore challenges that face absolutism, and it is reconcilable with an appealing emotivist approach to moral attitudes. In previous work, I have offered considerations in favor of a version of moral relativism that I call “perspectivalism.” These considerations are primarily grounded in linguistic data. Here I offer a self‐standing argument for perspectivalism. I begin with an argument against moral absolutism. I then argue that moral terms, such as ‘wrong’ and ‘right’, require for their application that the moral judge instantiate particular affective states, and I use this claim to provide further defense of moral relativism.     

A Peircean Theory of Decision

It is sometimes argued that the fact that possession of perfect knowledge about the future is impossible, means that it is impossible for decisions to be rational. This reasoning is fallacious. If rationality is given a new interpretation, then decisions can be considered rational. A theory of decision that has as its basis Peirce’s theory of abduction can provide a new way of understanding decisions as rational processes. The Peircean theory of decision (i) considers decisions as part of a complete strategy, and (ii) shows that decision making is governed by the same rules as scientific abduction. These rules are neither permissive rules like rules of deductive inference nor predictive like laws of nature, but rather genuine laws of conduct that determine what step should be made, if a given end is to be reached. This revised version was published online in June 2006 with corrections to the Cover Date.