Starting from Dennett's distinction between personal and sub-personal levels of description, I consider the relationships amongst three levels: the personal level, the level of information-processing mechanisms, and the level of neurobiology. I defend a conception of the relationship between the personal level and the sub-personal level of information-processing mechanisms as interaction without reduction . Even given a nonreductionist conception of persons, philosophical theorizing sometimes supports downward inferences from the personal to the sub-personal level. An example of a downward inference is (...) provided and an objection is considered. (shrink)

The broad issue in this paper is the relationship between cognitive psychology and neuroscience. That issue arises particularly sharply for cognitive neurospsychology, some of whose practitioners claim a methodological autonomy for their discipline. They hold that behavioural data from neuropsychological impairments are sufficient to justify assumptions about the underlying modular structure of human cognitive architecture, as well as to make inferences about its various components. But this claim to methodological autonomy can be challenged on both philosophical and empirical grounds. A (...) priori considerations about (cognitive) multiple realisability challenge the thesis on philosophical grounds, and neuroscientific findings from developmental disorders substantiate that challenge empirically. The conclusion is that behavioural evidence alone is inadequate for scientific progress since appearances of modularity can be thoroughly deceptive, obscuring both the dynamic processes of neural development and the endstate network architecture of real cognitive systems. (shrink)