Science, Reality, and Objectivity

Posted on May 22, 2018 by

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Our research project team members here in Calgary have spent the last several months reading (and re-reading) Bas van Fraassen’s subtle and powerful work Scientific Representation (2008). As with any work of its scope and ambition, it’s open to a heavy dose of interpretation. What follows is my interpretation, and I’ll stress that it is particularly heavy. In any case, the way this work appears from my perspective raises what I think are some fundamentally important questions: about what science is, how to interpret what it tells us about reality, and whether the reality it depicts is the only one there is.

My view of the book’s central aimーat least the one I find most useful to my own thoughtーis that it offers a sophisticated account of scientific objectivity. “Science is objective!”, says the echo reverberating through any debate about climate change, evolution, vaccines, or any other headline topic. But what exactly does that mean? For a scientific realist, this might mean that science tells us, or at least aims to tell us, what the world is really likeーwhat things there really are, how they really behave, and so on. There is a world, and it is a certain way regardless of what we believe about it, and it’s science’s job to break out of our subjective boxes and get to the objective reality outsideーthe real reality. So the realist might say.

The thing about empiricism, however, is that it denies that science tells us what the world is really like. In general, the empiricist thinks that science isn’t about describing the world as it really is but, for example, just allowing us to explain and predict the things we observe and manipulate the world more effectively. So does this mean that science isn’t objective after all? Is it just subjective? No it isn’t, says arch-empiricist van Fraassen: science isn’t just whatever we believe or want it to be. To say it is would fail to account for its undeniable power. But to see how science can be objective without telling us what the world is really like, we have to look deeply into how science “tells us” anything at all. In other words, we have to look at the way in which science represents the world; hence, Scientific Representation.

Firstly, what, in van Fraassen’s view, do scientific representations represent? What is its target? Answer: they represent phenomena. But he doesn’t mean this term in the same way as much of the philosophy of mind or phenomenology; his “phenomena” are not private impressions confined to our individual minds and inaccessible to others. They are the publicly observable stuff of our shared reality: tornadoes, populations of deer, stars, and so on. The job of science is to represent these phenomena. But not all representations are scientific: paintings in galleries represent their targets, but not in a scientific way. So the question is, what’s uniquely scientific about scientific representation?

To answer that, van Fraassen first looks at what representation is in general. His account, happily in my view, is thoroughly pragmatic: nothing represents anything except when it is used or taken to represent something. This means, among other things, that mere resemblance does not a representation make: in fact, the uses we have for representations often requires dissimilarity, selective resemblance. (This looks to be an early swipe at the idea that science represents reality as it really is.) As an illustration, we’re given a fascinating account of pictorial representation, including a history of the development of projective geometryーof how to project a three-dimensional scene onto a two-dimensional plane, a plane located in a particular place relative to that scene. The point is to show that pictorial representation represents a scene as it appears from a particular perspective. Doing so involves a range of distortions of that sceneーflattening, warping of shapes, and so on.

This brings us to what makes the difference with scientific representation. This involves two kinds of representation in science: measurement and models. Firstly, to measure something is to represent it: it represents its target as being a certain wayーof having a certain temperature, for example. Crucially van Fraassen takes measurement to be perspectival just like the pictures described above: they represent the target as it appears in that measurement setupーfrom a particular perspective.

So far, then, this doesn’t pull science apart from other forms of representation. However, we use measurement outcomes (under controlled experimental conditions) to develop and test scientific models. Unlike measurements, models give us what we might call a “perspective-independent” representation of their targetsーthey provide information about what results we should get from various experiments on that target; that is, the observations or measurement results we should expect from those experiments. (Indeed, this is just how we test those models: if they fail to predict what we observe, they’re quickly rejected.) A key example of this idea is Minkowski’s introduction of four-dimensional spacetime: In 3D space, your inertial frame of reference makes a big difference to what you experience, even to things as seemingly simple as the speed of a clock or the length of a “rigid” rod. But representing things in Minkowski spacetime tells you how things will look from any frame of reference. Hence, it is perspective-invariant, a view from nowhere in particular.

Here’s where things get really interesting. One might take the above as conceding that science actually does tell us what things are really like: Because the individual, subjective perspective has dropped out of the representation, doesn’t that mean that what’s left is objective reality? Not if you mean that it contains all that there really is and leaves out what is “merely” appearance. The reasons he gives are subtle. A major one is that, despite all of the above, scientific representation depends by its very nature on indexicality. Suppose you’re given a map representing the city you’re in. To use that map to get around (which is what it’s for) you have to be able to locate yourself on itーto point to somewhere on the map and say “I am here”. This usually requires looking around for street signs and landmarksーthat is, taking measurements from where you are. Often it’s more complicated than looking around, however: early seafarers did so by conducting a range of measurements of the angles of the stars from the horizon, and so on. Still, the aim of doing so was to figure out where “here” was. But as well as using models already developed, developing and testing models in the first place requires you to know where you are when you’re making the measurement, otherwise you don’t know what you should be seeing. This is the “essential indexical”: science depends on self-location, and this is not provided by the models.

The big lesson, as I understand it, is that to say that science is objective is not the same as saying that it describes reality as it actually is, behind the veil of mere appearance. Our advanced theories and instruments aren’t like a window into the previously opaque world or a more powerful set of eyes; they don’t extend the range of what is observable. It only makes us better able to explain, predict, and manipulate what is already observableーnamely, the phenomena. Those phenomena are most certainly real; any theory that doubts that trees are real isn’t worth taking seriously. Theoretical entities depicted in scientific theories may also be realーand you’re quite free to believe that they are, as many scientists do. But believing that they are real is not necessary for science to do its job. That is just not what science is for.

Scientific Representation is dense, rich, and generously rewarding of careful (and repeated) reading. Whether or not I accept van Fraassen’s conclusion that empiricist structuralism as the way to go (I’m not sure I do), I found in its pages an exciting take on the nature and aims of science that will remain in the foreground of my own thinking for a long time to come. In particular, reading it has helped me organise my thoughts about a question that all philosophers of science (I’d imagine) wrestle with: how to do justice to science’s power and successーand hence its commanding hold on our beliefs about the worldーwithout blind deference and the demise of every other realm of human understanding. In my view, this can be done by understanding that “objective reality” is not the only reality: to think that it is suggests that its complement, the subjective, is not real, merely an illusion. For me, this is bad naturalism: Subjects and their appearances are every bit as real, as much a part of the world, as objects are. Hence, understanding reality means understanding the complex relationship between the two, and how, ultimately, the two are interdefined and interdependent. While science in a sense aims to give us a view from nowhere, there is, in reality, no such thing. Everywhere we are, we are somewhere, and the function of science is to help us get around.

-Oliver

Reference

van Fraassen, B. C. (2008). Scientific Representation. Oxford: Oxford University Press.