Explanatory Realism

To begin with I distinguish various kinds of realism, especially commonsense, scientific and metaphysical realism. I then argue that all of them can be supported by explanationist arguments, among which I distinguish abduction, inference to the best explanation, and various forms of “no miracle” argument. Some of these arguments are based on first level explananda (empirical regularities and scientific phenomena), others on meta-level explananda (the success of science). Some are scientific inferences, some are philosophical. The “no miracle argument” is a meta-level philosophical argument, but some of its forms can be derived by equivalent transformations from first-level scientific arguments, so naturalists claimed that it is a scientific argument. While granting its scientific bases, however, I argue that it is distinctly philosophical, and philosophy is distinct, even if continuous with science. The no miracle argument is usually taken to explain scientific success by postulating the truth of theories, but both this explanandum and this explanans are found to be problematic. Instead, I take as explanandum the success of scientists in finding theories with unexpected predictions, and as explanans (so as conclusion of the argument) the actual finding of partially true theories, through reliable scientific method, thanks to the simplicity, uniformity and rationality of nature. Moreover, I claim that these explanations are not available to the various forms of idealism. Hence, while scientific and metaphysical realism are logically independent of each other, one can hardly support scientific realism by the “no miracle” without also accepting metaphysical realism.