Scientific realism

Varieties of (the problem of) realism Ontological: is there a mind-independent world? Epistemological: can we know something about the world? Semantic: does language refer to the world, and are statements true or false mind- independently? Methodological: can we develop scientific methods to pursue the truth? Axiological: are there (objective) values?

Global vs. local approaches to the realism issue Realism can be discussed globally, regarding the mind- independence, knowability, etc., of reality in general. –Michael Devitt: realism is a very general empirical thesis about the mind-independent existence of something (weak realism) or, more specifically, of commonsense and scientific entities. Realism can also be discussed locally, contextualizing the issue to one or another problem area: –Scientific realism about unobservable theoretical entities. –Realism about (e.g., ethical) values. –Realism about mathematical entities. –Realism in the philosophy of religion (God, religious language). –Realism about the past (cf. the philosophy of history). –…

Dimensions of scientific realism (1): ontological According to (typical) scientific realism, there is a world ”out there” (nature) that is largely independent of the human mind (e.g., perceptions, thought), of language and concepts, of practices (of scientific research, e.g., paradigms), of points of view, of cultural perspectives, etc. Realism can be ontologically stronger or weaker depending on whether it is maintained that the world just exists mind-independently or whether it is argued that the world is determinately the way it is (has the properties it has) mind-independently. –Strong ontological (metaphysical) realism: the world has its own ”ready-made”, pre-categorized ontological structure.

Dimensions of scientific realism (2): epistemological Only a very implausible form of scientific realism would claim that the world is knowable as a totality. Fallibilism: taking human fallibility seriously (cf. Peirce, Popper). –Any one of our beliefs or theories may be false. Perhaps all of them are false. –Strong fallibilism: all theories are false. –Weak fallibilism: some theories may be true, but we can never know which ones are. (We could always be wrong.) –Fallibilism must be distinguished from skepticism! The world can to some extent be known, despite human fallibility, and we can acquire more knowledge about it by developing better methods of inquiry.

Dimensions of scientific realism (3): semantic Language can be used to refer to (represent) mind- and language-independent reality. Theories of reference: how does language ”hook onto” the world? –E.g., causal, naturalized theories: reference is ultimately reducible to causal processes in the natural world. –The world itself – the real objects and processes there are – fixes the reference of our terms, including the theoretical terms used in science. Theories of truth: correspondence vs. others? –Minimalism: do we need a substantial theory of truth? –In particular, the scientific realist maintains that scientific theories are mind-independently true or false even when they speak about (refer to) unobservable theoretical entities. –Truthmaking: the world itself ”makes true” all truths.

Dimensions of scientific realism (4): methodological Science progresses toward the truth (regarding any particular cognitive question). Scientific progress can be understood, e.g., as the increasing truthlikeness (verisimilitude) of theories (cf. Niiniluoto), even though the truth itself is never easily attainable, or perhaps not attainable at all. –Truthlikeness can be used to compare theories that are strictly speaking false but that can get ”closer to the truth” as inquiry progresses. Scientific methods should be assessed in terms of their ability to lead us toward the truth, or to help us in the progress to increasing truthlikeness. Science is not mere practical problem-solving but attempts to formulate new true or truthlike theories.

Dimensions of scientific realism (5): axiological Truth (or knowledge understood as justified true belief?) is the proper goal of science (at least basic research) – cf. cognitivism. Truth and knowledge (or, possibly, truthlikeness) are central epistemic values to be pursued in science. However, the scientific realist is not committed to regarding non-epistemic (e.g., ethical) values as mind- independently or objectively ”real”. Some scientific realists are moral realists; others aren’t. (The same applies to other kinds of value, e.g., aesthetic.) –The value-ladenness vs. value-neutrality of scientific research: this issue will be revisited in due course.

Versions of (scientific) antirealism Ontological: subjective idealism, phenomenalism, solipsism, radical constructivism (e.g., Berkeley, Latour?) Epistemological: skepticism Semantic: nonrealist theories of truth, e.g., epistemic concepts of truth (e.g., Putnam in the 1980s) Methodological: conceptions of scientific progress as increasing problem-solving ability (e.g., Kuhn, Laudan); instrumentalist views on scientific theories as mere instruments for the prediction and control of observable phenomena Axiological: non-cognitivist conceptions of the aims and goals of science (e.g., instrumentalism)

How about idealism? Some views defended in the realism dispute may seem to be idealistic (e.g., social constructivism, Putnam’s internal realism). Whether this is a threat to the objectivity of science depends on what idealism means. Subjective idealism: the world depends on a subjective mind. Objective idealism: the world depends on a ”world-soul” (absolute spirit – cf. Hegel). Critical, transcendental idealism (Kant): the world depends on the transcendental structure of our cognitive faculty. –Modern versions of Kantianism in the philosophy of science: Kuhnian constructivism (the world depends on paradigms), Putnamian pragmatic/internal realism (the world depends on how we describe it through our schemes). –Kant must be taken seriously in the philosophy of science!