Although of primary importance in all branches of physics and an indispensable conceptual tool of scientific thought, the notion of mass seems to elude all attempts at a fully comprehensive elucidation and a logical as well as scientifically unobjectionable definition.
Throughout its long history in human thought, from its early adumbrations in Neo-Platonic philosophy, its mystic and still inarticulate presentation in theology, to its scientific manifestations in the physics of Kepler and Newton, to its carefully though-out redefinitions of positivistic and axiomatic formulations, up to its far-reaching modifications in modern theories of physics . . . nowhere does science seem to get full command and control over all the conceptual intricacies involved. One has to admit that in spite of the concerted effort of physicists and philosophers, mathematicians and logicians, no FINAL CLASSIFICATION of the concept of mass has been reached. 'The modern physicist may rightfully be proud of his spectacular achievements in science and technology. However, he should always be aware that the foundations of his imposing edifice, the basic notions of his discipline, such as the concept of mass, are entangled with serious uncertainties and perplexing difficulties that have as yet not been resolved.
Such clouds are the raw stuff out of which stars and planets are made. Appearing, disappearing, and appearing again in endless succession since the beginning of time in the Cosmos, they mark the FIRST STEP on the PATH to LIFE.
IN THIS ONE CLOUD, MAN'S FATE WAS SEALED. Within the cloud were the light gases, hydrogen and helium, mixed with smaller amounts of other substances. Carbon, nitrogen and oxygen was present, as well as such metals as iron and aluminium, and trace amounts of gold, uranium and other rare elements. Many of these substances would play an important role in the life that was to emerge from the cloud. Nearly all had been conceived in the hearts of other stars; few could trace their lineage to the original moment of creation. The atoms in the interior of the cloud, drawn to its center by the force of gravity, piled up to form a dense, hot mass. The temperature at the center of the cloud climbed; nuclear reaction flared up, and the sun was born.
The outer regions of the cloud - cooler and less dense - gave birth to the planet . . . The formation of the earth and its sister planets went on over a period of several million years, proceeding with extreme slowness at first and then with rapidly increasing momentum in the final stages . . .
When the earth came into existence, it was a naked body of rock without air or water; but a subtle transformation taking place in the depths of the planet would soon change that. . . . The earth was ready; it waited for life.
Which factor played the most important role in the development of human intelligence? Was it the pressure of the ICE-AGE climate? our tools? Or language? No one can tell; ALL WORKED TOGETHER, through Darwin's law of natural selection, to produce the dramatic increase in the size of the brain that has been recorded in the fossil record in the last million years. The brain reached its present size about one hundred thousand years ago, and its growth ceased. Man's body had been shaped into its modern form several hundred thousand years before that. Now brain and body were complete. Together they made a NEW and MARVELOUS CREATURE, CHARGED with POWER, INTELLIGENCE, and CREATIVE ENERGY. His wits had been honed by the fight against hunger, cold, and the natural enemy; his form had been molded in the crucible of adversity. In the annals of anthropology his arrival is celebrated by a change in name from HOMO ERECTUS - the man who stands erect - to HOMO SAPIENS - the Man of Wisdom.
The story of man's creation nears an end. In the beginning there was light; then a dark cloud appeared, and made the sun and earth. The earth grew warmer; its body exhaled moisture and gases; water collected on the surface, soon the first molecules struggled across the threshold of life.Some survived; other perished; and the law of Darwin began its work. The pressures of the environment acted ceaselessly, and the forms of life improved.
The changes were imperceptible from one generation to the next. NO CREATURE WAS AWARE OF ITS ROLE in the LARGER DRAMA; all felt only the PLEASURE and PAIN of EXISTENCE; and LIFE and DEATH were devoid of a greater MEANING.
But to the human observer, looking back on the history of life from the perspective of many eons, a MEANING becomes evident. He sees that through the struggle against the force of adversity, each generation molds the shapes of its descendants. Adversity and struggle lie at the root of evolutionary progress. WITHOUT ADVERSITY there is NO PRESSURE; without PRESSURE there is no CHANGE.
These circumstances, so painful to the individual, create the great currents that carry life forward from the simple to the complex. Finally, man stands on the earth, more perfect than any other. Intelligent, self-aware, he alone among all creatures has the CURIOSITY to ASK: HOW DID I COME INTO BEING? What forces have created me? And, guided by his scientific knowledge, he comes to the REALIZATION that he was created by all who came before him, through their struggle against adversity.
HUMANITY is the start of the race; I say HUMANITY is the MOLD to break away from, the crust to break through, the coal to break into fire, The atom to be split. Tragedy that breaks man's face and a white fire flies out of it; vision that fools him Out of his limits, desire that fools him out of his limits, unnatural crime, INHUMAN SCIENCE, Slit eyes in the mask; wild loves that leap over the walls of nature, the wild fence-vaulter SCIENCE, Useful intelligence of far stars, dim knowledge of the spinning demons that make an atom, These break, these pierce, these deify, praising their God shrilly with fierce voices: not in man's shape He approves the praise, he that walks lightning-naked on the Pacific, that laces the suns with planets, The heart of the atom with electrons: what is HUMANITY in this cosmos? For him, at last Least taint of a trace in the dregs of the solution; for itself, the MOLD to break away from, the coal To break into fire, the atom to be split.
Let observation with extensive view Survey MANKIND, from China to Peru.
These four achievements of human effort are so many gifts of grace which are neither to be taught or learned, neither given nor taken, neither withheld or earned, since they come through experience, which is something given and therefore beyond the reach of human caprice. Experienced cannot be made. They happen . . . . it is a venture which requires us to commit ourselves with our whole being.