Dr. Paul A.M. Dirac, 82, a Nobel prize winner in physics who was one of the founding fathers of the quantum theory, a landmark in man's understanding of the material universe, died Saturday at his home in Tallahassee, Fla.
After reaching the mandatory retirement age of 67 at Cambridge University in England, Dr. Dirac joined the physics faculty at Florida State University in Tallahassee. Although he had been ill for some time, he continued teaching until shortly before his death. The cause of death was not reported.
Dr. Dirac, who remained a British subject, shared the 1933 physics prize with Erwin Schroedinger, an Austrian. Both were ranked among the giants who revolutionized their science and opened the door to an understanding of the behavior of matter on the infinitesimally small scale of individual atoms and molecules.
Along with the theory of relativity pioneered by Einstein, the quantum theory dominates 20th century physics, providing a means of explaining and understanding the bewildering profusion of information about the subatomic world yielded by increasingly sophisticated experimental techniques.
From the precise mathematical system and structure set up by Dr. Dirac, Schroedinger and others of their generation came the theoretical foundations of much of modern technology, including advances in electronics, communications and computers.
In one of its first and fundamental achievements, quantum theory offered a plausible explanation for an experimental observation that had baffled the physicists of the early 20th century.
It explained how on the atomic scale, energy could be radiated not continuously, as classical physics demanded, but in small chunks or bundles that came to be called quanta.
Quantum theory explained what had been inexplicable by abolishing on the atomic scale the order, certainty and absolute predictability provided by classical theory. In their place it introduced the less definite notions of probability.
This idea, and another characteristic idea of quantum mechanics, that of dualities, specifically of the duality between the wave and particle nature of matter, had almost as much effect on modern philosophers as on physicists.
It also provided a means of treating on an equal and interrelated basis matter, energy and radiation, all of which had existed for 19th century science in separate and closed compartments.
Among the particular contributions made by Dr. Dirac with and to quantum theory was the prediction of the existence of the first of the so-called antiparticles.
While the electron, with its negative electrical charge, had been known for years, Dr. Dirac, through application of sophisticated mathematical techniques, asserted that an opposite particle, with many of the same characteristics, but a positive charge, also existed.
The theory was confirmed in 1932 by the observation of the positron. Dr. Dirac's prediction and the experimental work by Carl D. Anderson, pointing to the possible existence of entire antiuniverses of particles with properties opposite to those of their more mundane counterparts. To the delight of both physicists and fantasists, many such particles have been found.
Dr. Dirac was a native of Bristol, England, and received degrees from Bristol University and from Cambridge. In 1930 he became a fellow of the Royal Society. He won its Royal Medal in 1939.
He was also a member of the Pontifical Academy of Science and he said he agreed with Pope John Paul II that science and religion are not incompatible. "They are both seekers after truth," he said in a 1983 interview.
At Florida State he developed a theory that gravitational forces became weaker as the world grew older. Why? he was asked. "Why?" he said. "Because God made it so."