1 What is the ‘thickness’ of the present? Bergson’s dual perception system and the flow of time 1 Yasushi HIRAI (Fukuoka University) 1. Dual Visual System Hypothesis in Contemporary Cognitive Science Throughout the studies of agnosia, blindsight 2 , and visual illusions, it came to be known that we seem to have two independent visual systems, and many research programs are ongoing in order to identify their physiological substratum. For example, the distinction of ‘vision for action’ and ‘vision for perception’ maintained by Goodale and Milner (1992) is meant to have its neural correlate on the bifurcation between the ‘dorsal’ and ‘ventral’ stream at the exit of the Primary Visual Cortex (V1). In the case of blindsight, another neural bifurcation is located at the superior colliculus that exists before the V1. Whatever the physiological correlate may be, the most important thing, as a matter of fact, is that it becomes more and more probable that our bodies are capable of executing appropriate reactions without any assistance from conscious visual images. Blindsight patients can avoid balls or obstacles without having any visual representation. For example, D.F., who has lesions in the ventral stream, no longer has the ability to determine the orientation of a slit, though she can still smoothly put an envelop into it 3 . A sound person, having an erroneous representation by the effect of the Ebbinghaus illusion (e.g., circle b appears to him as bigger than a), would not be deceived in the movement of picking up an object (i.e., the widths between fingers are correctly the same) 4 . All these evidences strongly suggest the existence of a direct pathway from received stimuli directly to bodily reactions 5 , 1 This conference is supported by the Grant-in-Aid for Scientific Research (B) under Grant No. 15H03154 from the JSPS (Japan Society for the Promotion of Science). Website: http://matterandmemory.jimdo.com/ 2 In an international symposium held in Fukuoka in 2010, I discussed Bergson’s recognition theory, adapting it to the context of blindsight. Cf. Hirai (2010), L. Weiskrantz (2009), and especially the continuous works of Yoshida. 3 Milner and Goodale (1995). 4 Haffenden and Goodale (1998). 5 Limited to elementary, well-mastered, and stereotyped movements.