philosophy of science dead? realism vs. empiricism (Introduction)

by David Turell , Friday, September 09, 2016, 00:21 (2787 days ago) @ David Turell

An interesting discussion with a leading philosopher of science relating to our recent Higgs discussion: - http://nautil.us/issue/40/learning/-why-science-should-stay-clear-of-metaphysics - "In philosophical terms, “anti-realists” or “empiricists” understand science as investigating the properties of observable objects via experiments. Empirical theories are constrained by the experimental results. “Realists,” on the other hand, speculate more freely about the possible shape of the unobservable world, often designing mathematical explanations that cannot (yet) be tested. Isaac Newton was a realist, as are string theorists. - *** - "As the inventor of “constructive empiricism,” van Fraassen is widely acknowledged by his peers as one of the greatest living philosophers. (He calls himself “a philosopher's philosopher.”) Van Fraassen does not write for the philosophically uninitiated, but his books are in no danger of going out of print. - "In his 2008 book, Scientific Representation: Paradoxes of Perspective, van Fraassen argued that experimental data is nothing more nor less than a representation of an observable fragment of a fundamentally unobservable universe. He argued that while it is scientifically acceptable to believe that data represents a physical state of an “it,” that does not necessarily mean “it” exists. - "As the ineluctably empiricist philosopher, Ludwig Wittgenstein, quipped, “Whereof one cannot speak, thereof one must be silent.” And yet many scientists speak of unobservables as if they are embedded in a map of reality that can be discovered. - *** - "Science is walled off from metaphysics in van Fraassen's brand of empiricism by the demand that experimental data must correlate with at least part of the structure of a theoretical model. His bedrock notion of “empirical adequacy” stops at that, forbidding itself to speculate about the (metaphysical) nature of unobserved phenomena. - "Fortunately, constructive empiricism allows science to proceed without providing an ontological map of the whole shebang. By way of example, there is evidence for what goes on inside a proton, but that does not allow us to assume the existence of quarks. Tons of data from linear accelerators fit into an empirically adequate model of what quarks might be. But to claim that quarks exist is a metaphysical, not a scientific statement. - *** - "My main point is that it is practically impossible to describe the chaos of what actually happens in the world. We can construct useful theories or models that are empirically adequate—that tell us something, for instance, about the behavior of what we call electrons, without having to say what an electron is. Parts of a theoretical model can be judged as true or false, based upon the reproducibility of the data. But, to be useful, to be empirically adequate, the data does not have to fit into some overarching theory about the organization of the world. - *** - "It is a matter of fact whether or not electrons are real. The physical world is certainly real; it objectively exists, even though we cannot glimpse more than a tiny part of it. It is the role of science to make predictive theories about phenomena which we can observe, not what we cannot observe. We will never see the particle itself, only its representations, its images, but we strive to collect a body of data that enables a theory to predict what objects do. - *** - "Realism is also a stance, but, counter the empiricist, a realist is not necessarily constrained by the facts revealed by data. The role of science is not to interpret or explain a greater reality, but to create theories that are useful in making predictions about the observable world. The sole criterion of scientific success is empirical success. Theories survive by latching onto regularities in nature. - *** - "The constructive empiricist says that experimental results and measurement results are the only “real” phenomena that a scientist can witness. The criterion of success is fitting the experimental data into theoretical models that predict the data itself. - "By way of example, fitting data about Higgs bosons as imaged by the Large Hadron Collider to the predictions of the Standard Model does not mean the Standard Model is a true theory, just that the Higgs data corresponds to a piece of the theory which was not previously found to be empirically adequate. (my bold) - "The realist disagrees, “No! Empirical adequacy does not go far enough. The criterion of scientific success is that a theory has to be entirely true.” - *** - "To be clear, scientists tend to be pragmatists, not philosophers. The takeaway is that if the data conforms to a part of a theoretical scheme that strives to explain the structure of a chair or of the universe, that model can be used as a basis for designing more experiments. If the data does not fit the predictions of the model, then the theory is not useful for science, but fine for metaphysics, if that is what you want to do." - Comment: Note the bold about the Higgs. I am an empiricist. I fully understand that a quark is known by its manifestations, not as a quark itself. Multiverse theory is philosophic foolishness.