the neuro linguist addresses the fourth of our research questions: how is linguistic knowledge represented in the brain? It is easy to sympathies with the fundamental nature of this question, since we firmly believe that cognitive capacities are the product of structures in the brain. However, the direct study of the human brain is fraught with difficulties. Most obvious among these is the fact that ethical considerations forbid intrusive experimentation on human brains. Such considerations are not extended to non-human,with the consequence that the neuroanatomy and neurophysiology of non-human, primate visual systems, similar in their capacities to that of humans, are already understood in some detail. For language, however, we have to rely on less controlled methods of inverstigation, for example, by studying brain-damaged patients who suffer from language disorders. In these circumstances, the extent and precise nature of the damage is not known, a factor which inevitably contributes to the tentativeness of conclusions.