Those of you who’ve known me a while may remember that I dislike accepting philosophical labels. For example, although the labels “materialist” or “physicalist” are more or less accurate descriptions of what I think, they often seem to imply an ideological rigidity I’m not comfortable with. My attitude toward these labels somewhat resonates with Neil deGrasse Tyson’s:
I’m not an “ism.” I just – I think for myself. The moment when someone attaches you to a philosophy or a movement, then they assign all the baggage and all the rest of the philosophy that goes with it to you, and when you want to have a conversation they will assert that they already know everything important there is to know about you because of that association. And that’s not the way to have a conversation.
I agree, but sometimes forget about that agreement.
A few years ago, I asked what scientific theories tell us about the world. That post called into question the distinction between scientific realism and instrumentalism. Realism asserts that a theory actually reflects reality. So when general relativity predicts spacetime is warped, under realism, there is actually something “out there”, an actual spacetime actually being warped.
Instrumentalism asserts that theories like general relativity are just prediction mechanisms. It’s possible there is actually a spacetime that is actually warping, but we can’t know that. All we can know for sure is how accurate the theory’s predictions are. The classic instrumentalist example is Ptolemy’s ancient model of the universe, with the Earth at the center and everything else revolving around it in concentric crystalline spheres. Ptolemy’s model accurately predicted naked-eye astronomical observations, but we now know it was completely wrong.
However, what we call “reality” is itself just another theory, a model we hold in our mind. Its most primal aspects might be constructed by and verified with the senses, but it’s a theory nonetheless, one that can often be wrong. There is value in reconciling scientific theories with our model of reality. It seems to increase the probability that the theory actually models something real. But we can never be sure we’re not just operating under a paradigm, a way of thinking about reality, that might itself eventually turn out to be instrumental, as an assumption of a stationary Earth did .
My goal in that post was really to show the distinction between the outlooks was actually meaningless. However, in subsequent conversations, I started to be convinced that view effectively made me an instrumentalist. Eventually I took it to heart and started calling myself one.
And then over time relearned why I dislike labels, as people started making assumptions about my attitude toward various propositions. I’m an instrumentalist, they would reason, therefore I don’t care about whether a theory reflects reality. I’m an instrumentalist, therefore it shouldn’t matter to me whether a theory fundamentally makes sense, or whether it can be reconciled with other theories. I’m an instrumentalist, therefore I don’t believe in an objective reality.
In truth, these things matter a great deal to me and I do believe in an objective reality. We can never be sure a theory actually reflects reality, but I don’t want scientists to lean on that. I want them to aim for realist accounts, ones that are logically complete, that make causal sense, and can be reconciled with as many other theories as possible.
Of course, sometimes scientists have to accept an explicitly instrumentalist account. The classic example is Isaac Newton and gravity. Newton worked out the mathematics of gravity, mathematics that provided accurate predictions, at least to the extent that people in the late 1600s could test. But he had to admit that he didn’t know what gravity fundamentally was. That situation would last until 1915 when Albert Einstein came along with a new theory, one that explained gravity as the warping of spacetime.
Philosophically, Einstein was a staunch realist. In fact, most scientists are realists. It’s hard to spend years of your life gathering data or working out theories if you don’t see yourself in pursuit of truth. Building complex experimental machinery or going on expeditions to dirty uncomfortable and sometimes dangerous locations to build a mere prediction mechanism doesn’t seem very inspiring. Although in reality scientists tend to be realists about some theories and instrumentalists about others. In some cases, they can regard different constituents of a particular theory as real or anti-real.
Einstein’s realism famously made him reluctant to accept quantum mechanics as a complete theory. Arguably what we now call the Copenhagen interpretation was in its beginnings an explicitly instrumentalist or anti-real account. Many of the founders of quantum theory, such Niels Bohr and Werner Heisenberg, seemed satisfied with that instrumentalist account (perhaps under the influence of the then popular logical positivist movement). But Einstein couldn’t accept it.
My attitude is that Copenhagen (at least the weak epistemic version) was a good placeholder in the 1920s, and may still be. But it’s only a placeholder, just as Newton’s version of gravity was a placeholder. Of course, all scientific theories are provisional, subject to being replaced in the future with a better theory. But in the case of explicitly instrumentalist accounts, that replacement should arguably be more actively anticipated.
I think Einstein was right that investigations should have continued until we had a more complete account, or a more complete understanding of the existing one. But I can’t see that we’ll ever know whether we have a real account. All we can do is search for one that is causally complete and can be reconciled with other theories.
In that sense, I could be described as a descriptive instrumentalist, but not a prescriptive one. We should always strive for a realist account, just never get too comfortable that we have one.
All that said, I wonder if I shouldn’t avoid the instrumentalist label in the future. Although at least now I’ll have this entry to link to.
Are you a scientific realist, descriptive instrumentalist, prescriptive instrumentalist, or something else not mentioned? What led you to that position?