SIR KARL POPPER is a thinker and writer of some distinction, and it is extremely difficult to state the numerous strands of his thought in a short article. But there is one fundamental theme which seems to run through all his works relating to scientific method, and it is impossible to miss this theme if only because it is so forcefully stated. This article attempts to analyse the basic elements of this theme in order to assess its significance for students (...) of scientific method. (shrink)

This target article draws together two groups of experimental studies on the control of human movement through peripheral feedback and centrally generated signals of motor commands. First, during natural movement, feedback from muscle, joint, and cutaneous afferents changes; in human subjects these changes have reflex and kinesthetic consequences. Recent psychophysical and microneurographic evidence suggests that joint and even cutaneous afferents may have a proprioceptive role. Second, the role of centrally generated motor commands in the control of normal movements and movements (...) following acute and chronic deafferentation is reviewed. There is increasing evidence that subjects can perceive their motor commands under various conditions, but that this is inadequate for normal movement; deficits in motor performance arise when the reliance on proprioceptive feedback is abolished either experimentally or because of pathology. During natural movement, the CNS appears to have access to functionally useful input from a range of peripheral receptors as well as from internally generated command signals. The unanswered questions that remain suggest a number of avenues for further research. (shrink)

The book analyzes how one might philosophize about some of the most difficult and controversial issues in ethics and politics without abandoning either the demands of rigor or the joys of clear vistas.