HISTORICAL PERSPECTIVES IN TWENTIETH CENTURY CHEMISTRY' JACK J. BULLOFF Battelle Memorial Institute, Columbus, Ohio
TwEiwImH century chemistry shows a growth and application unparalleled in the history of chemistry. Currently it is criticized on two grounds. First, there has been a notable slackening in the rate of emergence of new basic ideas of the first rank, especially in the last two decades. Second, there has been an unprecedented expansion of applied chemical research, thought to beat the expense of basic research. Historical examination of twentieth century chemistry offers one may of putting such criticisms into perspective. The growth of tmentieth century chemistry is part of a vast new upsurge in the importance of scientific attitudes and accomplishments. The acceleration of the study and use of science in the twentieth century characterizes a second industrial revolution, more farreaching than the earlier industrial revolution first described by the elder Toynbee in 1870. Both industrial revolutions have occurred against the background of the unique historical development of intellectual and material power within Western Civiliaation.
HISTORICAL EVENTS AND HISTORICAL FORCES
History is concerned with events, with their int,eractions to give rise to yet other event,s, and with the merging of events and interactions to provide causal backgrounds for accumulations of human motivations whose influence is large in space and time. Accumulations possessing intellectual potency and commanding the exercise of material power are historical forces. At a given time and place historical forces shape events in a manner and in a measure that balks notions that mankind can easily govern more than its very immediate future. Historical events may either be important of themselves, or else they may only be important because t.hey are typical of a vast assemblage of similar events. Outstanding events are relatively rare. Latently outstanding events, like Lomonossov's anticipation of physical chemistry a century too early, count for little in history. Personal genius is equally unimportant unless exhibited a t the right time and place. Thus, outstanding events represent only a small proportion of the acts of decision or genius that men are capable of, and such capabilities are of themselves relatively uncommon. Events which do not require the exercise of more than ordinary capabilities occur much more frequently. I n the instance of everyday events, the frequence of occurrence of certain ones may be such that their interactions with each other and with related events
' Presented before the Division of History of Chemistry a t the 130th Meeting of the American Chemical Society, Atlantic Cit,y, September, 1956.
may constitute a growing historical force. Where a given number of events can inspire or influence a larger number of subsequent events, interactions may increase progressively in frequency, scope, and complexity. Carl Becker advanced as a principle of history the assertion that such progressive ramifications of events and forces must occur increasingly with the passage of time, thus shortening the time-scale of h i s t ~ r y . ~This phenomenon of history is known as 'Lself-acceleration." The combined effects of the self-acceleration of history in time and space, and of the cumulative influence of a few large and many small effects on human progress give to the history of human progress a character of flow and ebb. This ebb and flow can be used to mark history into periods. The periods of history show the common sequence of rise, flowering, and decline. In the history of intellectual forces, this sequence is exhibited as a cycle in which new ideas gain acceptance against dogmatic resistance, systems of thought based on the new ideas arise, the established systems become demonstrably inadequate, and newer ideas are born. The history of chemical ideas shows how several of these cycles of the intellect have occurred since prea,lchemistic days. The rise and decline of the alchemistic, iatrochemical, and phlogistic periods in the history of chemistry, and the rise of the period of chemistry based on the atomic-molecular hypothesis have been described in many publications. The decline of the "atomic-molecular" period in the history of chemistry has yet to be recognized despite its completeness. In today's progress, the upset of ideas is accompanied not so much by rejection as it is by reabsorption into a larger framework. This has served to obscure the fact that in recent chemistry intellectual changes have occurred more rapidly t,han is commonly realized. The chief feature of tmentieth century chemistry up to the present is the emergence of a new period in the history of chemistry, based on the fruits of a twentieth century revolution in physics which included the burgeoning development of subatomic knowledge. Western Civilization no longer operatesin centuries; in a very few decades the "electronic-nuclear" period in the history of chemistry has emerged and reached a startling maturity. Another feature of twentieth century chemistry is its involvement in the practical affairs of mankind. This goes much further than the mere use of chemical research in the technical assistance of industrial, agricultural, and extractive production. The impact of technological advances on the attainment of economic prosperity and national security has fostered a growing z B ~ CARL, ~ "Progress ~ ~ ~and , Power," Alfred A. Xnopf, New York, 1949.
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recognition of science's intellectual potency and material power. Factors as yet dimly seen are changing the appearance of chemistry both as a discipline and as a profession. THE SECOND INDUSTRIAL REVOLUTION
Modern Western Civilization orginated in a renascent zeal for human enlightment. Its unique feature has been the use of knowledge to seek more knowledge. Increasing enlightenment has brought to men the view that improvements in intellectual and material comfort are a birthright. The industrial revolution and the American revolution arose out of such ideas. At first technology used extant scientific results, and the engineer represented the forefront of expanding production. As industry began to encourage and then to direct research, the industrial scientist replaced the engineer as the architect of future technology. As this occurred, the time-scale of industrial progress shrank along with that of geographic distance and social progress. Changes in degree can become so great as to be changes in kind. Today's social outlook and material productivity differ from those of the days of Charles Dickens and Karl Marx as those of their time differed from those of the time of Shakespeare and Galileo. A second industrial revolution has emerged, and covers not only Europe but the world. Its intellectual leadership is American rather than European, and its spirit, especially in Asia, is that of the continuing American revolution of Parrington and Zucker, rather than that of nineteenth century nationalism. The second industrial revolution is not characterized by a one-sided impact of industrial research on society. Technology has revolutionized science fully as much as science has revolutionized technology. Scientists, once odd avocationists, and later academic ornaments, now form a numerous vital profession encountered by their fellow men in schools, in business, in public service, and in everyday news. A greater proportion of this larger number of scientists can devote more of their time to research than was heretofore possible. Progress in production and technology has given each research worker resources and equipment which multiply his hourly productivity m a n y f ~ l d . ~ This multiplication of productivity has interacted self-acceleratedly, and today a vast literature, in some 50,000 periodicals, speeds its present course but threatens, as i t grows beyond manageable limits, to limit the rate of its increase. The reorganization of knowledge and the creation of an improved profession to manage it are inevitable. Despite these looming prohlems, the need for more scientific productivity is so patent that enhanced scientific recruitment is on the program of all industries and all governments. I n Russia, the continuing counterattack against the technology of the democracies is on two fronts. The first, is the use of every means possible to force a climate within communism that will favor a greater growth in the numbers and productivity of scientists. The second is the demeaning of "Western Science" and a ROBINSON, SIRROBERT,"Organic Chemistry at the Crossroads," The Priestley Medal Award Addre~sbefore the 124th Meeting of the American Chemical Society, Chicago, September, 1953.
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the glorification of "Marxist Science," conducted essentially to conceal the fact that science itself is responsible for the inapplicability of Marxism as a criticism of history and as a blueprint for social progress. Marxism could only have competed against a static economic society incapable of creating mass markets for its mass products. Science gave capitalism its most dynamic aspects and promise. THE RISE OF TWENTIETH CENTURY PHYSICS
The doom of the ether and the heat-death of the universe brought the vast system of nineteenth century physics to a sharp crisis. Great ideas occur at rare intervals to rare spirits. Fortunately for physics, the genius of Planck and of Einstein came to the fore without too discouraging a wait. Acts of genius inspire others on occasion, and the first decades of the twentieth century found physics abounding with new experimental discoveries and new theoretical ideas bearing out the tremendous suggestions of the quantum and relativity theories. When old beliefs are in disrepute and uew ones have yet to crystallize, the chaos of nature is reinforced by the chaos of man's attempts to find the reassurance of order in nature. Surviving ideas and novel approaches are tied in odd harness and hitched to key problems. The earlier years of twentieth century atomic physics saw the rise and discard of the Rutherford, Bohr, Sommerfeld, de Broglie, Schrodinger, and Heisenherg dynamic models. By 1924 the description of the extranuclear atom seemed so complete that the study of assemblages of atoms and of atomic nuclei began to open diverging fronts in the new physics. Beginning attacks on the physical problems of atomic nuclei had as their byproduct the production of energies and materials that are of prodigious portent to man's future. Continuing attacks on these problems, especially in the higher energies more significant to meson than to nucleon study, seem to indicate that yet another intellectual upset is to occur in the basic concepts of physics. The fall of parity conservation and the failure of the unified field to mesh with particle field theory are but two signs that physics has to go quite far before it can regain the destroyed unity of nineteenth century physics. The part of the present revolution in physical thought which has most complete relation to chemistry seems either complete or in abeyance. The fields of physics in which basic activity is most fertile seem to be quite remote from direct connection with chemical phenomena as known today. It can be stated that for a quarter of a century, progress in physics has not upset the current bases of chemical thought. THE RISE OF THE "ELECTRONIC-NUCLEAR PERIOD
When physicists studied subatomic phenomena, chemists turned to it for explanation of valence, bonding, structure, reactivity, and numerous other questions not solvable within the atomic-molecular hypothesis. The dynamic models of the physicists inspired the early static models of atomic structure with which Kossel, Bury, Lewis, and Langmuir, among others, laid the basis for an electronic theory of valence. As quantum mechanics became a stabilized discipline capable of forefront utilization by chemists, work like
that of Linus Pauling set the stage for more detailed and accurate theories of valency and the chemical bond. A generation ago, quantum chemistry was as complete in principle as classical mechanics; in theory it included all chemical systems and could calculate their parameters completely, given suffirieut mathematical tools.4 Quantum chemistry has interacted with the older branches of chemistry and with some of the newer ones to form a new discipline of first rank importance, "chemical physics." Chemical physics is a system of chemical thought that has reached considerable maturity, and within it feverish discovery of new principles is not to be expected. This fact alone gives to twentieth century chemistry an aspect of slowed progress in the rate of production of basic ideas. This slowed progress is to be expected at this stage of development of the electronic-nuclear period of chemistry. Neither industry nor Soviet can do aught within this system to restore the appearance of pioneering progress of decades ago. This awaits still another scientific revolution from without the present system of chemical thought. The electronic-nuclear period in chemistry has seen the rise of new branches of chemistry, such as structural chemistry, nuclear chemistry, and geochemistry, in addition to that of chemical physirs. There have also been relative shifts in the rate of basic and applied growth among the older branches of chemistry. This has been caused largely by the remarkable resurgence EYRING, H., J. WALTER, G. E. KIIKBALL, "Quantum Chemistry," John Wiley & Sons, he., New York, 1944.
of inorganic chemistry, mainly in the second, and certainly into the third, quarter of the century. Analytical, physical, organic, and biological chemistry have benefited greatly by these developments, even though some of them have been rivals in attracting talents and funds. As phenomena beyond the grasp of atomic-molecular concepts have gradually been explained and coordinated by the use of electronic and nuclear ideas, the forefronts of nineteenth century chemistry have gradually been pushed either into the realm of elementary textbooks or into a group of highly specialized studies. The chemistry of today differs from that of Arrhenius, Ostwald, and van't Hoff as much as theirs differed from that of Priestley, Cavendish, and Black. This is the measure of the maturity of the electronicnuclear period in the history of chemistry. CONCLUSIONS
Twentieth century chemistry is yet to experience its greatest expansion. The electronic-nuclear period is well developed and gives chemistry today a powerful and useful system of chemical thought. The second industrial revolution increases the productivity of research greatly. New basic ideas of the first rank cannot occur within the now completed framework of chemical physics. Such ideas are not being inspired in chemistry by the new directions in modern physics. If such ideas are to arise in large numbers, they must come from advance in an area of science outside of quantum chemistry. The rise of applied research will not discourage such advance.
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