critics had attacked the Newtonian scheme on the basis of alogical flaw in it. It first postulates that the position and velocity of any particle can be determined in isolation from all others. Then it postulates that there is a complete and continuous interaction of all these particles with one another. Logically, the two postulates nullify each other. But as long as the principles involved gave satisfactory results this objection was brushed aside or ignored. Heisenberg's prin- ciple compels arecognition of the fact that interaction prevents an accurate measurement of velocity and position for any body,