Philosophy of science: concepts and methods

Philosophy of Science: Hempel vs. Holism

It is a shame that in scientific debate philosophies of holism and reductionism have been considered mutually exclusive, when a combined approach is plausible and even logical. Hempel himself admits to subjectivity concerns with his treatment of hypothesis, but no one would argue that an approach to holism is possible without a thorough understanding of the elements of a holistic system. The virtue of reductionism is in its elementary utility, it is a paradigm easily applicable with clear-cut causal definitions: if H. then I; not I; not H. Through reductionism modern science has been built, brick by brick, from the ancient Greeks, to Copernicus and Galileo who melded into Newton, and finally to relativity, quantum mechanics and string theory. However, utility and tradition are not synonymous with truth. From a positivist viewpoint, it is necessary to accept holism -- and has been at least since Heisenberg proposed his Uncertainty Principle. Like Newtonian mechanics, Hempel's theories suffer from generalized application: on the level of barometers and mountain-tops there is causal continuity, but in more complex systems the approach breaks down. Simple, reducible hypothesis elude many fields to this day -- notably economics, where no two experts yet agree on the precise phenomena leading to this past decade's recession. While understanding the reduced elements -- sub-prime mortgages and credit swaps -- contribute to understanding of the whole, there is an interaction still un-described occurring in the interstitial spaces; a ghost in the machine.

Hempel's argument for radicalism in the selection of hypothesis is too narrow to encompass a universe of phenomena. The Pascal experiment is simple enough to be dominated by reductionist conclusions, just as the motion of planets is simple enough to be dominated by Newtonian mechanics. However, many experiments in physics cannot explain their results as simple summations of the work of individual elements. The collapse of wave functions in quantum mechanics is one example. The interaction of the observer with the whole system in observing it informs and manipulates the destinies of individual particles -- electrons say -- which are collapsed from a pre-observation, indeterminate state into a single observable state. In order to describe the famous double-slit experiment it was not necessary to radically change the central hypothesis of wave-particle duality but was correct to re-examine, from a holistic viewpoint, the system and make a conservative change to the corollary, un-expressed hypothesis that an observer can remain wholly separate from his experiment. As Duhem would have it: not I; so not H. Or not A1 or not A2 or not AN.

In the case of wave function collapse we also have one instance of a higher-complexity layer of a system affecting the state of a lower-complexity, reductionist element. If the holistic layer -- the backdrop against which the electrons splash and are observed -- is able to interact with the reductionist layer -- the electrons themselves -- we arrive at a failure in Hempel's theory. The double-slit experiment cannot be fully described by understanding only electron motion.

Another telling and interesting example appeared in the April 2010 issue of Discover Magazine. In an article titled "Back From the Future" by Zeeya Merali, an American physicist, Jeff Tollaksen, reports that he was able to influence measurements taken in an experiment by decisions made an hour or more after the measurements were taken. Tollaksen is a researcher concentrating in the field of reverse causality, the idea that both the past and the future affect the present. His results, if fully accepted, defy any sort of reductionist explanation. A necessary reductionist viewpoint -- a reductionist assumption a holist might say -- is the flow of time, and all particles trapped therein, from low entropy to high. Causality is central to reductionism. Yet, in Tollaksen's experiment, by the time the decisions -- the causal phenomena -- are made, the measurements -- the affected phenomena -- are not only already over but all the reduced elements involved with those measurements already dissipated, destroyed, or gone wherever it is photons go when physicists are done with them. Tollaksen's experiment suggests that Pascal's barometer reads 30 inches of mercury not just because of what the atmospheric pressure is (at which it arrived by being what it was) but also because of what the atmospheric pressure will yet be.

Of course, it is impossible to say that reductionism should be discarded. Approach to holistic understanding begins necessarily with reductionist understanding of individual elements. Who could hope to understand the recent recession without knowing about credit swaps? Where would Tollaksen be if he had never been to Physics 101?