While a student of Arnold Sommerfeld at Munich in the early 1920s Werner Heisenberg (1901–75) first met the Danish physicist Niels Bohr. He and Bohr went for long hikes in the mountains and discussed the failure of existing theories to account for the new experimental results on the quantum structure of matter. Following these discussions Heisenberg plunged into several months of intensive theoretical research but met with continual frustration. Finally, suffering from a severe attack of hay fever, he retreated to the treeless island of Helgoland. After days spent relaxing and swimming Heisenberg suddenly experienced the giddy sensation of...

The Copenhagen interpretation of quantum theory, which grew out of discussions between Niels Bohr and Werner Heisenberg, included Leon Rosenfeld (1904–75) as one of its major proponents. Born in Charleroi, Belgium, Rosenfeld made his intellectual home in the Copenhagen of Bohr. In addition to his discoveries in theoretical physics Rosenfeld became the major apologist of the Copenhagen school after Bohr’s death.

Our interview with Professor Rosenfeld took place in Copenhagen and was one of his first activities after suffering a heart attack. Later we dined with the Rosenfelds and, after spirited discussions, toasted the memory of his friend and...

In one of C.P. Snow’s early novels a character in the scientific life of Cambridge is described as the successor of Newton. It can only be Paul Dirac (1902–). Like Newton before him Dirac has made contributions that are respected by his colleagues not only for their depth of insight and clarity but for the power and economy with which mathematics is brought to bear upon the problems of nature. Dirac’s scientific papers have the polished and balanced appearance of a sculpture by Brancusi.

While Heisenberg was discovering the principles of quantum mechanics in his Helgoland retreat, Erwin Schrodinger...

Roger Penrose’s professional career began in pure mathematics. Born in Colchester, England, in 1931, he obtained a doctorate in mathematics from St John’s College, Cambridge. His interests turned to the study of space-time structure and he spent a number of years at several American universities before returning to England.

His contributions in theoretical physics reflect his mathematical background for he seems quite at home when moving through multidimensional spaces, projecting infinities, or dissecting hyperspheres. With his imaginative approaches he has established important theories on singularities in space-time which have bearing on the nature of black holes. His insights into the...

John Wheeler is a physicist whose mind has the combination of inventiveness and independence that seems so characteristic of American men of talent. Born in Florida in 1911, Wheeler studied with two of the greatest men of science, Albert Einstein and Niels Bohr. Those who knew Bohr say that Wheeler's combination of courteous attention and encouragement to others, no matter if they are established scientists or students at the start of a career, is a reflection of his teacher.

In addition to making contributions in the fields of nuclear physics, atomic structure, and relativity theory John Wheeler has encouraged a...

Professor Weizsäcker (1912–) is Director of the Max-Plank Institute at Starnberg, Germany. He began academic life as a physicist and his abilities were soon recognized by Werner Heisenberg, who co-opted him to his team of brilliant young scientists. As a member of this research group Weizsäcker was to make important contributions to the theory of nuclear structure.

Professor Weizsäcker, like his mentor Heisenberg, has a deep interest in philosophy which has taken him to the Chair of Philosophy at Hamburg University. To the professions of philosopher and physicist can be added a third: political scientist.

We spoke with Professor...

Born in Moscow in 1917, llya Prigogine went to Belgium at an early age and has spent the whole of his scientific career there. He is a professor at the Free University of Brussels and also holds an appointment as director of the Center for Statistical Mechanics and Thermodynamics at the University of Texas at Austin. Professor Prigogine’s most important contributions to science have been in the fields of statistical thermodynamics and non-equilibrium thermodynamics. Non-equilibrium processes are characterized by energy flows, fluctuations which may be amplified, and emergence of structures. Structures maintained in non-equilibrium situations are called ‘dissipative structures’ and...

The participants in this discussion are, with the exception of Paul Buckley and David Peat, theoretical biologists.

Robert Rosen was born in Brooklyn in 1934 and obtained a Ph.D. in mathematical biology from the University of Chicago. He is a Killam Professor at Dalhousie University, but at the time of this interview he and Howard Pattee were colleagues at the Center for Theoretical Biology at the State University of New York at Buffalo. His interest in the mathematics of organization at the biological level resulted in his invitation to the Centre for the Study of Democratic Institutions where he has...

David Bohm is Professor of Theoretical Physics at Birkbeck College, the University of London. Born in Wilkes-Barre, Pennsylvania, in 1916, he gave some hint of his future scientific vocation when he displayed a childhood interest in mechanical devices and planned to make his fortune as a boy inventor. About this time he had sensations of the ‘interconnectedness’ of the world, a revelation which appears to have influenced his later thinking.

Bohm studied physics with Ernest Oppenheimer and, as a young research physicist, voiced his concerns over the foundations of scientific theories to Albert Einstein at Princeton. Bohm’s “early research on...