According to Milner and Goodale’s dual visual systems (DVS) theory, a division obtains between visual consciousness and motor action, in that the visual system producing conscious vision (the ventral stream) is distinct from the one guiding action (the dorsal stream). That there would be this division is often taken (by Andy Clark and others) to undermine the folk view on how consciousness and action relate. However, even if this division obtains, this leaves open the possibility that con- scious ventral information (...) is often transmitted to the uncon- scious dorsal stream and then used to guide action, a possibility seeming to preserve a significant role for consciousness in action. This article assesses this possibility. In course of doing so, we will review those arguments recently having been made against the DVS view on how visual consciousness and action relate (ones due to, e.g., Briscoe and Schwenkler, or Schenk and McIntosh). What we will find is that, if we properly analyze the data upon which these arguments are based, we are still left with the impression that the DVS view is largely correct; i.e., it is only rarely that visual experience guides action. (shrink)

Milner and Goodale's Two Visual Systems Hypothesis is regarded as common ground in recent discussions of visual consciousness. A central part of TVSH is a functional model of vision and action. In this paper, I provide a brief overview of these current discussions and argue that there is ambiguity between a strong and a weak version of PAM. I argue that, given a standard way of individuating computational mechanisms, the available evidence cannot be used to distinguish between these versions. This (...) not only has consequences for philosophical theories of the role of visual consciousness but also for the role of experimental evidence in model testing in cognitive neuroscience. (shrink)

My central claim is that philosophers of mind have failed to take adequate account of empirical evidence regarding human consciousness and vision. Experiments on split-brain patients over the past fifty years reveal consciousness in both cerebral hemispheres. I claim specifically that (a) consciousness in the right hemisphere is inherited from our animal ancestors; (b) consciousness in the left hemisphere arose during human evolution in association with language; and (c) the existence of both forms of consciousness provides the best explanation for (...) many aspects of normal human experience. Evidence for two cortical visual pathways in the human brain has been expanding for twenty years. The ventral pathway is specialised for object identification, and the dorsal pathway for the control of actions in respect of those objects. The evidence has been challenged by those who have failed (a) to distinguish between the visual pathways themselves and processes served by the pathways, and (b) to recognise the specific circumstances in which actions draw on one pathway. I claim that in the left hemisphere only the ventral pathway reaches consciousness. The combination of two visual pathways with two centres of consciousness challenges traditional views about perception. I claim that (a) perception is distinct from seeing; (b) perception is limited to the left hemisphere; and (c) the parallel process in the right hemisphere is associated with the emotions. The presence of two centres of consciousness challenges traditional views on the unity of consciousness and on personhood; but it also offers an explanation for conflicting views on the emotions and the existence of self-deception. I distinguish my claims about human consciousness from the Dual Systems (or Two Minds) Theory. Although there are superficial parallels, the latter theory denies that both systems/minds are conscious, and takes no account of the specialisation of the cerebral hemispheres revealed by experiments on split-brain patients. I conclude that philosophy must incorporate empirical evidence if it is to avoid claims of irrelevance. (shrink)