ERWIN SCHROEDINGER (1887-1961) received the Nobel Prize in physics for his discovery of new productive forms of atomic theory. In 1935 Schroedinger published "The present situation in quantum mechanics" where he made the following thought experiment. A cat in a closed box is either alive or dead according to whether a quantum event occurred. The paradox is that both the dead and living cat coexist. They coexist seemingly in parallel until an observer opens the box and looks at the cat, i.e., performs an experiment and forces the quantum system into a classical state, where only one or the other state exists, unlike the strange coexistence of two quantum states.

Erwin Schroedinger's essay 'What is Life' presents a physicist's view of the molecular world of living organisms. Written in 1944, it explained why the physics of his time was inadequate to give a complete description of the molecular mechanism of life. It is the realization of what can be summarize as the Large and the Small. Schroedinger, who made a major contribution to quantum mechanics, realized that there is no physics known that can bridge the laws of the very small and the laws of the very large (to which life belongs while making extensive use of the very small). This physics is still not elaborated or discovered (see also Roger Penrose) and represents the incompatibility between gravitational mechanics and quantum mechanics.

This reduction of the large to the small has also been addressed by Isaac Newton, who devoted much of his life to the study of alchemy in search of the forces that hold the very small together to produce the very large. Schroedinger lived in a time when Newton's questions have been answered in the form of quantum mechanics. As Schroedinger points out, it is important to realize that quantum mechanics is a statistical science and is only exact for large numbers of molecules, but can only give probabilities for small numbers of the same molecules. But living organisms are a complex composition of a small number of molecules and an exact treatment of the molecular mechanism in terms of a deterministic view is impossible. There are simply too many possibilities as understood by quantum states. We have to rely on macroscopic measurement (that's when we see the cat alive or dead) which are essentially governed by classical mechanics, and we take those macroscopic measurements to interpret mechanisms at the molecular, or quantum mechanical, level of matter (the chemical bond). However, there is no exact treatment (or solution, as mathematicians would say) to correlate classical with quantum mechanical  theory.

What is truly astounding is Schroedinger's ability to predict the function of macromolecules found in cells as they pertain to the cellular activity of organisms. He correctly described the implication of nucleic acid and protein structures on the very function of these macromolecules. For a physicist, these biological macromolecules are tremendously large, complex, asymmetric structures. Schroedinger is one of the first to clearly formulate this idea and his essay is as important today as it was fifty years ago.

May 30, 1999 /  © 1999 Lukas K. Buehler / go back to Book Review Home

We often find that our thoughts have been thought about by someone else before. Schroedinger brings us back to the ancient philosophers where we find many of the modern concepts used in particle physics (the nature of the atom, for example). The question, however, has to be posed why those ancient thinkers did not develop any equivalent technology. Why, for example, did the Romans not develop air crafts, although they were versed in the mathematics and physics of aerodynamics. Why would we bother about finding out? Well, it is human nature and we really do want to find answers that convey meaning about things, not just how they work. I first came across this way of thinking when attending a lecture on the history of science by the late Max Thurkauf, Professor of Physical Chemistry at the University of Basel, Switzerland, a nuclear physicist who made a very radical turn for a scientist, focussing first on the why and then on the theological dimension of life. He proposed a trinity of head, hand, and heart (he was a Catholic) to explain just this question about the Roman's lack of modern technology, while having all the philosophy available. As Thurkauf saw it, the Romans were focusing on head and heart, and not the hand, i.e., technology. The human mind is always tempted to find similarities and give more weight to things that bear resemblance. Schroedinger mentions the 'peculiar fundamental features of the present-day scientific world-picture' as intriguing and likely to be the product of historical development (against logical necessity). To read through this collection of short essays on diverse philosophical schools is enlightening. It demonstrates, that good scientists always have questions in mind that are bigger than science while definitely outside the scientific realm.

'Science and Humanism', the second part of the volume, does for physics what Ernst Mayr's 'Toward a new philosophy of biology' does for biology. Here, Schroedinger discusses the conceptual dimension of physical laws, theories, and models and dwells in the secular reasoning of causality, not only for physical objects as defined by Newton's laws of actio and reactio, but the problem of free will and the seeming frustration that comes with scientific determinism, for the latter contrasts with our perceived independence of thinking and creativity. As quantum mechanics appears to describe a physical world without determinism (a view strongly resented by Albert Einstein), Schroedinger seeks solace in this new physics that might well bring us a corresponding philosophy of mind explaining our experience of free will, the central promise of secular humanism.
 

December 30, 1999 /  © 1999 Lukas K. Buehler / go back to Book Review Home