. . "At the first annual lecture held in memory of Paul Dirac at St. John's College in Cambridge, England, Richard Feynman discusses the physical reality underlying Dirac's prediction of antimatter. Steven Weinberg discusses how tightly quantum theory and relativity together constrain the laws of nature and speculates that Einstein's theory of gravitation will be reconciled with quantum theory." . . . . . "1986 Dirac memorial lectures" . . . "Dirac memorial lectures" . . . . "Elementary particles and the laws of physics the 1986 Dirac memorial lectures" . . . . . . "Scientific Consulting Services." . . . .