(This is a paper I wrote for some class or other several many years ago. I didn’t like it back then, but thought I’d post it anyway.)
What is the essence of science, and what makes it successful? A survey of 20th century history of the philosophy of science will provide a full array of answers to these questions, spanning the spectrum of antirealist opinions, as well as touching on realist opinions. In Theory and Reality, Peter Godfrey-Smith introduces a framework to tackle these questions that consists of what he calls three “rival” perspectives regarding the “success” of science:
1. An Empiricist Approach. Science is an accumulation of knowledge through experience, and the success of science is from the reliance of our ability to refine our observational tools.
2. Mathematics and Science: Science is successful because of its use of mathematical tools and models to understand the world.
3. Social Structure and science: Science is successful because of its social structure which consists of Scientific Societies, Journals for peer review, and Research Programs.
There is so much strength in each of these positions that in his The Trouble with Physics, Lee Smolin looks to Paul Feyerabend’s anarchic abandon for comfort: that there are no general rules or descriptions and there cannot be any general rules of descriptions that define successful scientific practice. Demarcation between what is scientific and what is not cannot happen. This differentiation between what is and what is not science is considered the Problem of Demarcation. As discussed by Karl Popper, the differentiation is a methodological one. As discussed by Kuhn, science evolves in a cyclic fashion through paradigm shifts, so that any such distinction is vague. For Nancy Cartwright, the practice of science is the development of a patchwork of models – both mathematical and not – that need not correspond to reality. According to Cartwright, in fact the laws of physics are never true except in highly idealized situations that never “exist”. This paper will consider the three ‘essences’ of science propounded by these three philosophers with consideration of 20th century physics for a determination of the accuracy of their accounts for the success of science.
In his paper entitled Conjectures and Refutations, Karl Popper propounds his philosophy of science. For Popper, science is progressive through a continuous cycle of conjectures and refutations based on outcomes of crucial experiments, and his demarcating criterion is his principle of falsifiability. In particular, if a conjecture is such that it can be falsified in principle, i.e. that a crucial experiment can be devised where the outcome would decisively show that conjecture to be “true” or “false”, then it is science. In this sense then, Popper’s science is based on methodology. Although, it is questionable as to whether he believed that complete knowledge was attainable. His philosophy only explicitly stated that scientists only gather conjectures with increasing “corroboration”.
On this view, good scientific practice involves the immediate abandon of “falsified” conjectures. From a practical standpoint, this has neither been practiced, nor is it practicable. Taking a look at 20th century physics, one will find a long list of counterexamples:
Although Popper eventually said that a scientist need not abandon a conjecture immediately upon evidence against it, he did not have an unambiguous answer as to how long to wait. In the case of the Feynman Double-Slit Experiment for electrons, the outcome of this experiment shows that sometimes the result of what is considered a ‘crucial experiment’ neither decisively corroborates nor refutes a conjecture. In this experiment, an electron gun double-slit experiment was devised to determine the nature of the electron. If an interference pattern was observed on the screen, then the electron must be a wave. If a regular distribution is observed, then it must be a particle. The results of this experiment were such that even when one electron was “shot” at a time, an interference pattern was observed on the screen. This would imply that it is a wave. However, when the set-up is altered to determine which slit the electron is going through, the interference pattern collapses, and a regular distribution is observed, so as to indicate that electrons are particulate. In this case, the crucial experiment as devised by Feynman was not “decisive”. It did not lead to a clear “refutation” of the particle/wave theory of the nature of the electron.
The case of the Bohr model of the atom is an example of a model that is still in use because of its usefulness for calculation, but that has been shown to be false. The Bohr model of the atom consists is akin to the planetary model: a nucleus being ‘orbited’ by electron(s). With the knowledge of the wave-nature of the electron, Louis de Broglie developed a model of the atom with the electron as standing waves that surround the nucleus. However, for consideration of phenomena such as of spectral lines, the Bohr model, although not “true”, is more useful for making calculations. Similar to cases like these are Newton’s Law of Universal Gravitation: we learned from Einstein that gravity is not a “force” but a result of the curvature of space due to the presence of matter. In spite of this, Newton’s Law of Universal Gravitation as a model is more easily applicable for simple calculations.
Mathematically, this states that the product of the uncertainty in location and the uncertainty in momentum of an object must always be greater than or equal to h/2π (where h=Planck’s Constant). The consequences of the statement are profound. They include: (1) that there are limits to our ability to know what is really going on in the world, (2) there is no such thing as a passive observer. But for the sake of this essay, it is important to mention because Popper’s philosophy of science makes no use of the “Principle”. This principle is not falsifiable in principle: no one has yet determined even a thought experiment that could potentially show this to be false. Yet, it is not abandoned as an example of bad science.
In The Structure, Thomas Kuhn argued for a paradigmatic view of science: normal science is characterized by consensus and adherence to a paradigm. Science goes through cycles: chaos, normal science, anomaly, crisis, revolutionary science. His primary example is the development of physics from what he calls the Aristotelian paradigm to that of Newtonian mechanics, and finally to the Einsteinian one: there is incommensurability between paradigms, and each paradigm outlines the central beliefs of the scientific community at that period of time within that particular field (in this case, broadly speaking, physics). This was one of the biggest upsets for philosophers of science because, as Imre Lakatos believed, it reduced the practice of science to non-rational judgements.
His philosophy of science was strict, such that only one paradigm could dominate a field at any given time, and that normal science was characterized by consensus within that field, and particularly that it is this consensus that drives the success of science. What about research programs? Twentieth century physics is filled with competing research programs that have propounded what can be considered successful results.
Here are some examples:
On the existence of anti-matter, both Dirac and Feynman has mathematically equivalent theories, but different models for understanding. Dirac’s model of antimatter appeals to a visualization of a positron as the anti-electron. Feynman’s model does not appeal to the positron as a separate entity from the electron: he views it as an electron moving backward through time. Since they are mathematically equivalent, it is only the interpretations that differ. Why does this matter? Kuhn argued that development and success within a given paradigm required consensus. Here we see competing camps, with similar success. They need not view the world in the same way to build on their models.
Similar to the comparison between Dirac and Feynman on antimatter, in the 1920’s, Heisenberg and Schrödinger each developed mathematically equivalent quantum theory models. Unlike the discussion on antimatter, however, the understanding was similar. Divisions between the two camps were ideological. Heisenberg’s Matrix mechanics reduced quantum phenomena to the purely “observable” (i.e. to wavelengths, and intensities of spectral lines). Schrödinger’s Wave mechanics as a description of quantum mechanics appeal to a duality in the nature of the electron. As an illustration, consider Schrödinger’s Cat Paradox, in which he considered the cat 50% alive AND 50% dead at the same time. It is the action of opening the box that collapses the probability wave.
Neglecting the philosophical issues surrounding the rationality of theory choice, we can see that Kuhn’s portrayal of science was far too simple to account for twentieth century physics. Perhaps, at best, it could only best apply to outdated traditions.
The current figure in the philosophy of science is Nancy Cartwright, and her view that the laws of physics are never “true”, in the sense that they are only applicable to idealized situations. She makes a distinction between scientific models and scientific theories, and claims that truth lies in a patchwork of scientific modelling. The more true a law becomes, the less explanatory it becomes because of the additional stipulations required to make it so. One of her prime examples is that of Newton’s Law of Universal Gravitation which states that the force of gravity exerted between two bodies is inversely proportional to the square of the distance between them. Nancy is at issue with the situations under which such a law is applicable: (1) the masses of the two bodies must be considered point-masses, (2) the law is limited to two bodies. Her question is simply: When does a situation like this ever exist? The more additions made to a law to make it applicable to reality, she says, the more it loses explanatory power. Consider the following models drawn from twentieth century physics:
Spacetime. Discussion on the Special Theory of Relativity introduced the speed of light, c, as a conversion factor for the measure of time: to change the units of the measure of time from seconds to meters. Now with a 4-dimensional model of the universe, visualization becomes impossible. We can devise mnemonic devices to facilitate understanding, set-up comparisons with 2-dimensional and 3-dimensional worlds, but this not the same as “understanding” or “visualizing” time as a fourth dimension. The mathematics of the model work, but conventional understanding is lost.
Wave-particle duality. This is a return to the discussion of quantum mechanics. Schrödinger’s Wave mechanics call for a probabilistic view of electrons and photons. The reality of an electron is every possible situation simultaneously, until the probability cloud is “collapsed”. This is not something that can be visualized, and so not something that is understood in a conventional sense. The implementation of the model is to facilitate computation more than understanding.
Nancy Cartwright does not appeal to the establishment of scientific laws as Popper does for the development of science. The success of science is carried out through the ‘patchwork of models.
Lee Smolin’s appeal to Paul Feyerabend’s philosophy that ‘anything goes’ seems like the only answer to the question of the essence of science that can account for the practice of twentieth century physics. But this is hardly satisfying. To say that there is no absolute eternal essence to science leaves the door open to include anything as science. This is crucial because, as Imre Lakatos puts it:
“The problem of demarcation between science and pseudoscience has grave implications also for the institutionalization of criticism. Coopernicus’ theory was banned by the Catholic Church in 1616 because it was said to be pseudoscientific. It was taken off the index in 1820 because by that time the Church deemed that facts had proved it and therefore it became scientific. The Central Committee of the Soviet Communist Party in 1949 declared Mendelian genetics pseudoscientific and had its advocates, like Academician Vavilov, killed in concentration camps; … The new liberal Establishment of the West also exercises the right to deny freedom of speech to what it regards as pseudoscience, as we have seen in the case of the debate concerning race and intelligence…The problem of demarcation between science and pseudoscience is not a pseudo-problem of armchair philosophy: it has grave ethical and political implications.”
As regards what makes science successful, this is also constantly changing. Nancy Cartwright has put forward the argument that it is a patchwork of scientific models that comprise successful scientific practice. This account is the best descriptive formulation for current practice in physics. This is not to say that there are not useful normative elements of Popper’s and Kuhn’s philosophies. In spite of Popper’s philosophy’s inadequacy in determining decisive criteria for theory choice, his Conjectures and Refutations still describes a useful methodology to theory choice and research. Thomas Kuhn’s theory advocates the validity of there being a subjective nature to theory choice.
Returning to the three ‘rival’ perspectives introduced by Peter Godfrey-Smith of what science is and what makes it successful, twentieth century physics seems to leave the answer as indeterminate. The role of experimentation in physics has developed so greatly that the image of doing arm-chair physics is incomplete. Mathematics provides models for science, it also serves as tools for science, but it does not explain an idea, and it does not develop experimental techniques. Finally, the social structure of science accounts for all of the actual activity that exists in the formal fields of science. It is hard to imagine these three being rivals because out of all of the examples taken from twentieth century physics, it appears that all three descriptions of the enterprise of science together account for its success.
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Godfrey-Smith, Peter. 2003. Theory and reality : An introduction to the philosophy of science. Chicago: University of Chicago Press. Pg.8
Smolin, Lee. 2006. The trouble with physics : The rise of string theory, the fall of a science, and what comes next. Boston: Houghton Mifflin Co. Pg. 290-295
Philosophy of science : The central issues1998. , eds. J. A. Cover, Martin Curd. 1st ed. ed. New York: Norton. Pg. 2-9
Philosophy of science : The central issues1998. , eds. J. A. Cover, Martin Curd. 1st ed. ed. New York: Norton. (Cartwright)
Philosophy of science : The central issues1998. , eds. J. A. Cover, Martin Curd. 1st ed. ed. New York: Norton. Pg. 2-9
Philosophy of science : The central issues1998. , eds. J. A. Cover, Martin Curd. 1st ed. ed. New York: Norton. Pg. 2-9
Philosophy of science : The central issues1998. , eds. J. A. Cover, Martin Curd. 1st ed. ed. New York: Norton. Pg. 10-19
Godfrey-Smith, Peter. 2003. Theory and reality : An introduction to the philosophy of science. Chicago: University of Chicago Press. Pg.8 — Look up lakatos’ comment in godfreysmith’s book about not liking kuhn’s philo.
Godfrey-Smith, Peter. 2003. Theory and reality : An introduction to the philosophy of science. Chicago: University of Chicago Press. Pg.201
Godfrey-Smith, Peter. 2003. Theory and reality : An introduction to the philosophy of science. Chicago: University of Chicago Press. Pg.201
Philosophy of science : The central issues1998. , eds. J. A. Cover, Martin Curd. 1st ed. ed. New York: Norton. Pg. 26
Philosophy of science : The central issues1998. , eds. J. A. Cover, Martin Curd. 1st ed. ed. New York: Norton.
Bowler, Peter J. 2005. Making modern science : A historical survey, ed. Iwan Rhys Morus. Chicago: University of Chicago Press.
Godfrey-Smith, Peter. 2003. Theory and reality : An introduction to the philosophy of science. Chicago: University of Chicago Press.
Greene, B. 2003. The elegant universe : Superstrings, hidden dimensions, and the quest for the ultimate theory. New York: Vintage Books.
Hawking, S. W. 1990. A brief history of time : From the big bang to black holes. New York: Bantam Books.
Lightman, AlanP. 2005. The discoveries : Great breakthroughs in twentieth-century science. 1st. Canadian ed. ed. Toronto: A.A. Knopf Canada.
Smolin, Lee. 2006. The trouble with physics : The rise of string theory, the fall of a science, and what comes next. Boston: Houghton Mifflin Co.