A heretic’s take on scientific realism

by Neil Rickert

Note that the “heretic” in the title refers to me, and comes from this blog’s title.

I have long considered myself a scientific realist.  At least, on some definitions, a scientific realist is one who believes that science provides the best available descriptions of the natural world.  And, in that sense, I surely am a scientific realist.

I’ve been noticing that some people have been suggesting that I am an instrumentalist or an anti-realist.  So they must be using a different notion of “scientific realism.”  There’s a post, today, at Scientia Salon which gets into such an account of scientific realism:

Here, I will discuss that post and where I have difficulty with the way that it looks at science.  My own view of science, and how it works, should be apparent from that discussion.  And I think it will be clear that my own view is non-standard (and, in that sense, heretical).

The standard picture

The opening paragraphs of the cited post already suggest the standard view from philosophy of science.  It poses the “problem” of scientific realism in the form of the question “what is the status of scientific theories?”  It then breaks this down into details, and I’ll comment on those:

  • Should they [scientific theories] be interpreted as literal descriptions of reality?

To that, I’ll answer “No”.

  • Or are they rather predictive instruments, tools for interacting with reality?

I can go along with the idea that they are tools for interacting with reality, but I’m not so sure about the “predictive instruments” part of that.

  • Or perhaps they are mere social constructions?

There’s no doubt that they are social constructions, but there is nothing “mere” about them.

The author then divides the question into metaphysics, semantics and epistemology.  So I’ll separately look at those.

Metaphysics

Metaphysical question: does nature, the object of scientific inquiry, exist independently of our conception and observations of it? Idealists and radical constructivists would deny that it does.

I’m a skeptic of metaphysics, and this metaphysical question is no exception.  It seems to me that the question is vacuous.  The only meaning we have for “exist” is one based on our experience.  So any talk of “exist” can only be about our conception of reality.  We cannot get outside of that.

Some people suggest a God’s eye view, that we take “exist” as it would be to an imagined God.  But we create our gods in our own image, so the gods that we imagine are as limited by our conception of reality as we are.

I will say that I am not an idealist, and I do not take myself to be a radical constructivist.  I see theories as constructs, but I do not see reality itself as a construct.  However, we are still unavoidably limited by our own conception of reality.

Semantics

Semantic question: what makes theories true? Are they literal descriptions of nature? Is there a direct correspondence between language (including formal languages or mathematical models) and the fundamental constitution of nature, or does the meaning of our theoretical statements reduce to their conditions of verification? Instrumentalists would typically opt for the latter view.

There’s already a complexity here.  We use the term “theory” rather broadly, and theories are not all of the same nature.  So I’ll mainly be commenting on what I see as the most ideal theories.  I would put Newtonian mechanics in that class.

So now look at the details of that question:

  • what makes theories true?

Edict; authoritative assertion.

I see theories (or ideal theories) as analytic truths.  That is, they are true by virtue of the meanings of the terms that they use and define.  So, in some sense, they declare their own truth.

  • Is there a direct correspondence between language (including formal languages or mathematical models) and the fundamental constitution of nature

Yes.  But this is where I most strongly disagree with the standard view.  You cannot say that statements correspond to reality unless there are some principles of correspondence available.  As I see it, the primary role of science is to establish those principles of correspondence.

Take, for example, Newton’s laws.  They allowed us to talk about the force of air resistance or the force of friction.  They allowed us to assign numeric values to these forces.  So they established a correspondence between statements we could make and what is happening in reality.

It is this establishing of a correspondence that makes our theories analytic truths.  And it is also what makes our theories valuable.

Epistemics

Epistemic question: are we in a position to know that our theories are at least approximatively true? Empiricists would say that, inasmuch as our theories pretend to say more than what is verifiable at the level of observable phenomena, we are not in a position to know that they are any more true than (perhaps unconceived) alternative theories with as much empirical confirmation.

If our theories are analytic, then they are true.  However, my preference is to say that they are neither true nor false.  Their real role is to establish a correspondence, such as would make it possible to have observation statements that follow such a correspondence.  And those observation statements are true to the extent that they follow the correspondence defined by the theory.

However, it is not sufficient for our theories to be true (in the sense of analytic truth).  We also want them to be useful.  They establish a correspondence, but for the theory to be useful, that correspondence must enable useful observation statements.  So there is a strong pragmatic requirement for a scientific theory.

Theory change, then, amounts to a change of our principles of correspondence.  The change from geocentrism to heliocentrism is a classic example of this.  We typically make the change on a pragmatic base.  We change theories when the new theory provides a more useful or more comprehensive correspondence between the statements that we can make and reality.

How science works

The author of the Scientia Salon post goes on to say:

One of the main arguments for scientific realism, once formulated by Putnam, is that realism is the only position that does not make a miracle of the predictive success of science. The point being that anti-realists have no convincing explanation for the impressive success of science (notably for making novel, unexpected predictions), while realists have a simple one: our theories work because they correctly describe reality.

This seems mistaken, to me.  To say that scientific theories need to be descriptions of reality, is to say that scientists are akin to journalists.  In some sense, it sees scientists as journalists reporting on the natural world.

We do not expect journalism to lead to a lot of useful predictions.  So it is not obvious that a journalism of nature would lead to predictions.

Historically, before our modern scientific era, science (then called natural philosophy) was close to being a journalism of nature.  And it did not have the degree of predictive success that we have seen in modern science.

My view is that science works so well, specifically because it establishes correspondences between nature and our description.  This establishing of correspondences has allowed us to describe the world if far more detail than was previously possible.  It is the extra information, due to this increased detail, that I see as the basis for the success of science.

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6 Comments to “A heretic’s take on scientific realism”

  1. Thank you for this comment on my article.
    I don’t find your views that much heretic–they are pretty close from that of the logical empiricists actually (in particular your stance toward the metaphysical question, and analicity) or perhaps Putnam’s internal realism.
    What bothers me is your understanding of correspondence. I think this is merely a verbal dispute. The correspondence theory of truth assumes that nature (or reality) is independent of our concepts or observations, and that there is a correspondence between our concepts and reality. It cannot be the role of science to express this correspondence. That would require being “outside itself” in a sense. The correspondence must be conceived of as transcending our representations.
    I think you would deny that (because you reject the metaphysical question as meaningless and envisage that science establishes the correspondance “internally”). Per my understanding you reject the semantic proposition of scientific realism.
    Regarding your comparison with journalism: okay, the formulation was elusive, but what I meant was: our theories correctly describe the *fundamental constitution* of reality, which is predictive. In any case your view that theories are analytic somehow clashes with this. How could they be predictive at all?
    You say that science establishes correspondences with nature, but do you hold that nature is in some sense constituted or constructed by science? Or independent of our representation (which contradicts your rejection of the metaphysical question)?

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    • The correspondence theory of truth assumes that nature (or reality) is independent of our concepts or observations, and that there is a correspondence between our concepts and reality.

      That couldn’t really work.

      We send space ships to Mars. We use them to form representations. Then we make our conclusions about what Mars is like from those representations.

      I’m seeing correspondence as the basis for a theory of reality, rather than as a basis for truth.

      In any case your view that theories are analytic somehow clashes with this. How could they be predictive at all?

      Theories are not predictive. It is theory+data that is predictive. And the data is not analytic.

      You say that science establishes correspondences with nature, but do you hold that nature is in some sense constituted or constructed by science?

      I guess that depends on what you mean by “nature”, and people differ in their meanings.

      I would take nature to be independent of our science, but how we understand and describe nature is dependent on science (or on perception and perceptual learning, which I see as analogous to science).

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      • I am just reporting how truth has been considered by philosophers over the centuries: either correspondance to reality, or pragmatic utility, or coherence. If correspondance “couldn’t work” I suggest you to engage with the literature on the subject (your example with Mars is not illuminating: why would it entail that our representation do not correspond to how Mars really is?). Now if you just mean that you don’t endorse that theory of truth, well that’s what I was saying too.

        You mean that it is analytic that, following such observation in the present, another observation will occur in the future. The future is deduced a priori from the present. Hard to swallow.
        If our theories can’t be false: what do you make of theory change?
        Unless you believe that theories create the phenomena they describe I don’t think this view is consistent.

        If you take nature to be independent of science, and our representations of it in general, then you accept the metaphysical move of realism (contrarily to what you say in the post).

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        • I am just reporting how truth has been considered by philosophers over the centuries: either correspondance to reality, or pragmatic utility, or coherence.

          The reason that philosophy has competing theories of truth, is that none of them actually work.

          I’m looking at this from a scientific perspective. Suppose that I wanted to build an artificial person (this is only hypothetical). What abilities would I need to give that artificial person, so that it could discern truth in something like the way that humans do? As far as I can see, neither correspondence nor coherence provide any guidance.

          why would it entail that our representation do not correspond to how Mars really is?).

          As best I can tell, the expression “how Mars really is” has no actual meaning.

          You mean that it is analytic that, following such observation in the present, another observation will occur in the future.

          That’s a strange misunderstanding.

          No prediction is of that form, as far as I know. All predictions depend both on theory and uncertain data, and they all depend on additional assumptions such as that no unexpected contingency will arise.

          If our theories can’t be false: what do you make of theory change?

          Theory change also involves conceptual change. The old theory is still as true as ever about the old concepts, but not about the new concepts.

          If you take nature to be independent of science, and our representations of it in general, then you accept the metaphysical move of realism (contrarily to what you say in the post).

          I merely expressed an opinion about independence, and only because I took you to be asking for my opinion. Nothing depends on it. It provides no guidance to that hypothetical design of an artificial person.

          I have no objection to people expressing opinions.

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          • The problem is not how a person could know what is true. The problem is what truth is, metaphysically speaking. The realist says it’s a correspondence to reality. Once you accept reality exists (imagine for one second being a realist) the theory seems consistent and unproblematic. How does imagining an artificial person inform the debate? What do you mean by “not working?” What are your expectations exactly?
            Are you aware of the arguments against pragmatist theories of truth as assertability by ideal epistemic agents (e.g. that it does not respect basic logical principles, such as bivalence)? I have the feeling that’s where you’re going to. No problem with that, but that does not mean that other theories are inconsistent and that your own doesn’t face difficulties also.

            Your conception of the meaning of theories is similar to that entertain by Kuhn. You’ll need to face challenges from Kripke and Putnam’s arguments and direct reference. It does not seem true that the meaning of terms change with new theories (whales are always whales, whether they are considered mammals or fishes). It doesn’t seem true that theories cannot be compared, or more simply, that they cannot be false. It seems that a theory that earth is flat is simply false, not that the meaning of earth (or flat) differs in this theory.

            In any case you’ll be in pain of explaining the predictive success of theories (or theories+data+auxilliary assumptions if you insist). You did not answer this point.

            Well I guess your view that theories of truth “don’t work” (whatever that means) is an opinion, too.
            .

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          • The problem is what truth is, metaphysically speaking.

            This presupposes that truth is something.

            I’m reasonably satisfied with Wittgenstein’s “meaning is use”. We don’t need to look for a metaphysical nature of truth. It suffices to look at how it is used in every day life.

            Are you aware of the arguments against pragmatist theories of truth as assertability by ideal epistemic agents (e.g. that it does not respect basic logical principles, such as bivalence)?

            I don’t actually favor a pragmatic account of truth. I omitted that from my “provides no guidance” statement, because it could be said to provide some guidance.

            As for ideal epistemic agents — as best I can tell, they would be mindless zombies. Everything important about human agents is related to their not being ideal.

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