Heinlein, Robert A – Expanded Universe

mathematical intuition; a few hundred have lived in circumstances permitting use of

it; a smaller fraction have been mathematical physicists. Of these a few dozen have

left permanent marks on physics.

But without these few we would not have science. Mathematical physics is

basic to all sciences. No exceptions. None.

Mathematical physicists sometimes hint that experimentalists are frustrated

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pipefitters; experimentalists mutter that theoreticians are so lost in fog they need

guardians. But they are indispensable to each other. Piling up facts is not

science-science is factsand-theories. Facts alone have limited use and lack meaning;

a valid theory organizes them into far greater usefulness. To be valid a theory must

be confirmed by all relevant facts. A “natural law” is theory

repeatedly confirmed and drops back to “approximation” when one fact contradicts it.

Then search resumes for better theory to embrace old facts plus this stubborn new

one.

No “natural law” of 500 years ago is “law” today; all our present laws are

probably approximations, useful but not perfect. Some scientists, notably Paul

Dirac, suspect that perfection is unattainable.

A powerful theory not only embraces old facts and new but also discloses

unsuspected facts. These are landmarks of science: Nicolaus Copernicus’ heliocentric

theory, Johannes Kepler’srefining it into conicsections ballistics, Isaac Newton’s

laws of motion and theory of universal gravitation, James C. Maxwell’s equations

linking electricity with magnetism, Planck’s quantum theory, Einstein’s relativity,

Dirac’s synthesis of quantum theory and special relativity-a few more, not many.

Mathematical physicists strive to create a mathematical structure

interrelating all space-time events, past and future, from infinitesimally small to

inconceivably huge and remote in space and time, a “unified field theory” embracing

10 or 20 billion years and light-years, more likely 80 billion or so-or possibly

eternity in an infinity of multiple universes.

Some order!

They try. Newton made great strides. So did Einstein. Nearly 50 years ago

Dirac brought it closer, has steadily added to it, is working on it today.

Paul Dirac may be and probably is the greatest living theoretical scientist.

Dirac, Newton, and Einstein are equals.

Paul A. M. Dirac

The experimentalists’ slur about theoretical physicists holds a grain of

truth. Newton apparently never noticed the lovely sex in all his years. Einstein

ignored such trivialities as socks. One mathematical physicist who swayed World War

II could not be trusted with a screwdriver.

Dirac is not that sort of man.

Other than genius, his only unusual trait is strong dislike for idle talk.

(His Cambridge students coined a unit the dirac-one word per light-year.) But he

lectures and writes with admirable clarity. Taciturn, he is not unsocial; in 1937 he

married a most charming Hungarian lady. They have two daughters and a son.

He can be trusted with tools; he sometimes builds instruments and performs

his own experiments. He graduated in engineering before he became a mathematical

physicist; this influenced his life. Engineers find working solutions from

incomplete data; approximations are close enough if they do the job-too fussy wastes

man-hours. But when a job needs it, a true engineer gives his utmost to achieve as

near perfection as possible.

Dirac brought this attitude to theoretical physics; his successes justify

his approach.

He was born in Bristol, England, Aug. 8, 1902, and named Paul Adrien Maurice

Dirac. His precocity in mathematics showed early; his father supplied books and

encouraged him to study on his own. Solitary walks and study were the boy’s notion

of fun-and are of the man today. Dirac works (and plays) hardest by doing and saying

nothing . . . while his mind roams the universe.

When barely 16 years old, he entered the University of Bristol. At 18 he

graduated, bachelor of science in electrical engineering. In 1923 a grant enabled

him to return to school at the foremost institution for mathematics, Cambridge

University. In three years of study for a doctorate Dirac published 12 papers in

mathematical physics, 5 in The Proceedings of the Royal Societv. A cub with only an

engineering degree from a minor university has trouble getting published in any

journal of science; to appear at the age of 22 in the most highly respected of them

all is amazing.

Dirac received his doctorate in May 1926, his dissertation being “Quantum