Realism for Realistic People: A New Pragmatist Philosophy of Science

How to assess the accuracy or truthfulness of a map? One way is to check whether we can use it to get home from our present location. If our journey proceeds without difficulties, we may credit the map. We could test its reliability further by planning other itineraries. Much successful travel due to a representation (the map) warrants our saying that that representation is accurate or true. Chang mentions in passing the example of the map (a widespread example in epistemology, at least since Leibniz's day) but does not use it in the development of his argument. It appears, however, to encapsulate his book's key claim: “A proposition is true to the extent that there are operationally coherent activities that can be performed by relying on it.”If Chang does not treat the example of the map in any detail, that is because its most common use is to defend the correspondence theory of truth, according to which a representation (a map, a proposition, a theory) is true because it corresponds to reality. The problem, as Chang notes, is that we do not have an unmediated access to reality by which we could verify the correspondence. As in the correspondence theory of truth, Chang agrees that reality is mind-independent (it exists even if we do not think of it); notwithstanding, our access to reality is always, as Chang argues, mind framed. In the case of the map, we can verify whether a building or a hill is in the precise location indicated, but to do so we must already have some concepts that frame the buildings and hills that we seek. Thus, the map, even if accurate, does not correspond to reality as such, but to reality as we have framed it.We frame reality in ways that facilitate some of our activities. Hills, for instance, do not exist as such; perceiving hills is one way of cutting reality. We could cut it differently. Paying attention to hills, locating them on maps, helps us decide whether to take one route or another. On Google maps, if we ask for a bicycle route home, gradients will be indicated, but not if we are riding by car. Paying attention to inclinations (to hills) is important in some sets of activities but not in others.The definition of truth that Chang proposes is an elaboration of that advanced by William James: “ ‘The truth’ . . . is the expedient.” What is expedient, in James's sense, does not depend on our wishes (contrary to a pervasive misreading of pragmatist philosophy). Rather, the expedient depends on how reality reacts to our way of framing it. My wish to ride my bike where there are no hills does not make the absence of hills a true idea, and taking the idea as true will cause me to expend more energy than necessary in riding up inclined roads.Realism in the philosophy of science postulates that a reality exists independent of our thoughts and perceptions, even if nothing can be said with certainty about it. Chang, on the other hand, wants us to speak about reality—to experiment with and test our ideas about it. Even if we have no direct, mind-unframed access to it, we constantly interact with reality; we can thus try out our ideas and see if they are felicitous. Hence the adjective, activist, that Chang applies to his form of Realism. He also writes (as in the book's title) of “realistic realism”: a form of Realist philosophy of science for people with “a sensible and practical idea of what can be achieved or expected.”Jamesian pragmatism, as defended by Chang, allows for degrees of truthfulness. A representation becomes truer each time more activities can be performed based upon it. Chang's pragmatism allows for pluralism as well. A city, to continue with my example, can be mapped in various ways: showing the streets, the canals, natural elements, altitudes. Each sort of map is useful for some sets of activities but not for others. So there is no reason why they cannot coexist.What is easily accepted concerning maps is more difficult to accept or even to conceive when speaking of theories. Doing so demands extensive recourse to history. In this book, the argument is largely philosophical, but Chang has published two previous books where history is more important. In Inventing Temperature (my favorite), he revisits the history of the thermometer from the seventeenth through the nineteenth centuries. In Is Water H20?, he defends the theory of phlogiston, an old idea that is generally regarded as obsolete but that, according to Chang, was set aside for bad reasons. He argues that the phlogiston and thermodynamic understandings of heat could very well coexist and help us to construct fruitful divergent research programs. In Realism for Realistic People, Chang underlines the reasonableness and the advantages of the pragmatic and pluralistic epistemology that he already practiced in his previous works and that seeks to encourage scientists to pay attention to more aspects of reality.