scientific realism

"Look Ma, no things!"

   Realism is a stubborn habit. A particularly familiar (and formidable) version of a theory of objects is held by the scientific realist, who adds that those objects out there, with which we sometimes collide, and at other times collude, are the objects described by physical science—tables, chairs, and ultimately protons, neutrons, and things of that sort. Yes, things. It is the belief of the scientific realist that he trips over these hard, immutable pieces of bed rock in the formulation of his scientific theories, and that the world is constituted the way these theories say as a matter of scientific fact.¹
   Science purports to tell us in what objects the universe ultimately consists, and it is such an account of things that would be thrown up to the virtual reality theorist, who would have us believe that we construct infinitely numerous, equally real worlds out of the sensations or "raw feels" with which the knowledge process somehow begins.²
   However, science knows these objects—which are inferred objects—through theories having to do with them—theories that postulate of these objects one sort or another of property. To be sure, science knows its inferred objects only through hypothetical properties attributed to them by theories. All of which is to say, more exactly, that theoretical science does not know its inferred objects at all, but knows only properties. And this knowledge of properties is a tentative sort of knowledge at that. It is only as firm as the least shaky of our theories.
   Take astronomical phenomena, for example. What do we know of the planet Venus apart from its distinctive properties as a planet; i.e., its relative reflectivity, absorption characteristics, orbital features, axial inclination, and so forth? What do we know of this object apart from those properties that are attributed to it by the theories in which it appears as an object? What did we know of the planet Neptune before it was first seen? We knew the properties that a yet-undiscovered planet would have to have in order that the anomalous behavior of other, perceptible, scientific objects might be explained. Of course, the planet Neptune was eventually seen.
   What about Quasars—those as yet unexplained sources of X-rays located by astronomers at such immense distances from the earth? Are there objects at the other end of these X-rays? If so, what could we know of them over and above the properties that we might come to ascribe to them? Could we ever know anything about Quasar-objects apart from our Quasar-theories? The best we could do is say that there exists an X such that X possesses all the properties presently attributed to Quasars, but this is not to say that X enjoys any existence independent of our relational knowledge of it. To the contrary, it is to admit that X may be nothing over and above what our theories say it is. Xs are not substances, or substrates, or things.
   We come to similar conclusions when the scientific objects under consideration are not too big or too far away to be seen, but are too small. The entities of microphysics are in-principle too small to be seen, and consist more clearly still in those properties, and only in those properties, that our somewhat fickle and shifting theories predicate of them. Take electrons, neutrinos, Psi-mesons, protons, and the like. Fundamental particles are too small to reflect or diffract a ray of light, and so we have only indirect evidence for their existence—this evidence having to do with the behavior of directly observable physical objects, in so far as these objects are thought— through our theories—to be affected by the fundamental particles in question. Electrons, for example, are `seen' in the form of condensed water droplets in Wilson Cloud Chambers—such condensation triggered, according to our theories, by the passage through a hyper-saturated vapor of a particle having such and such charge, mass, velocity, and so forth. Similarly, Alpha-particles are evidenced by the clickings of scintillation counters—never bumped into or felt. Our factual evidence for the existence of neutrons includes the success of fission-type chain reactions. But where, in these cases, is the realist's hard, cold, object of knowledge—existing independently of our knowledge of it? It is nowhere to be found, of course. Microphysical entities are known only via their properties, where these properties are never inspectable themselves, but are predicated of the scientific object by certain theories.³
   Judging from the evidence that science is able to bring forward, external objects turn out to be hollow at the core—an empty suit of clothes—and so if it was some bed-rock, substantival "stuff" which we were looking for, which would anchor one view of the world, and not another, the anchor is absent. There is no man inside of the suit of clothes we caught.
   However, this result is not good enough if we are looking to a theory of objects to provide a razor able to distinguish real experiences from unreal or "virtual" ones. When all objects turn out to be hollow—all equally fictitious—they don't cut one way or the other. Understood as empty but useful foci of relations, the existence of objects external to ourselves serves as well to explain the occurrence of sensations within a reality chamber, as outside that same chamber. And so we must be prepared to hear participants in synthetic experiences taking comfort from the view that there are hard things in relation, out there, which are the ultimate causes of those experiences— that the world really is the way it would have to be in order to produce current sensory data, notwithstanding the fact that we may have made the machines which created those sensory data.
   Science works as well within the reality simulator as it does outside the reality simulator.
   "Look Ma, no things."
   When the thing goes, the adjective "virtual" loses its meaning.

¹ "I refute you thusly!" said Dr. Samuel Johnson, as he banged his fist on Bishop Berkeley's table. You just can't argue with things, goes this commonsensical argument.

² This view of things is called Phenomenalism. Philosopher critics complain that it may be accurate as far as it goes, but that it does not go far enough.

³Norwood Russell Hanson, a highly stylized and entertaining Yale professor who flew a Bearcat fighter plane to work (and one day into the side of a mountain, as it transpired) made this argument in the 1960s, much to the delight of his students. Professor Hanson quoted widely from the work of Neurath, Popper, Grunbaum, and from the other members of the so-called Vienna Circle. See his book The Logic of Scientific Discovery.