Philosophical traditions often bear the seeds of their own destruction.Their seminal insights are achieved in part by ignoring or distorting certain aspects of human experience. Insights and mistakes grow from the same roots. In transitional periods, this dialectic leads to strange reversals in allegiance and to unexpected and even unnoticed shifts in philosophical doctrine. Classical empiricism presents an example of this when one shifts attention from its treatment of epistemological questions to problems of humanaction, or to the relation of knowledge and action. The empiricist analysisof knowledge in terms of the succession and conjoining of ideas and impressions in the mind leaves the mind itself a passive spectator that undergoes its contents. On this view, the human subject lacks any distinctive spontaneity or power of initiative. The mind's internal processes are conceived ofon analogy with Newtonian mechanics and are distinguished by their law-likeregularity. The subject is not, and cannot conceive itself as being, a kindof agency. Historically, the consequences of this are evident in Berkeley's difficulties regarding ‘active spirit’, of which we have ‘notions’ but not perceptions, and in the often remarked upon disparities between Parts I and III of Hume's Treatise.