Some Thoughts on Hacking's Discussion of Experimentation

Ian Hacking’s Representing and Intervening (1983) includes a discussion of experiments, their role in science, and their relationship with observation and theory. Hacking argues that theory is not necessary for observation or experimentation in science, and undermines the view that the dependence of modern experiments on complex apparatus shows that the resulting observations are loaded with the theory of that apparatus.

Hacking points out that while one needs a theory to construct a microscope, one doesn’t need such a theory to ‘see’ through a microscope. He argues that most of us do not understand the theory behind microscopes, but don’t need that understanding to learn how to use them. Moreover, before Ernest Abbe showed that a microscope works by the diffraction of light in 1873, scientists held an incorrect theory about how a microscope works, but good microscopes were constructed by purely empirical experience. In other words, we do not learn to see through a microscope by reasoning through the theory; and neither do we simply learn that by looking at it. We rather learn by doing and tinkering with the things we see.

The question that is raised here is whether theory is required to justify that what we see using an apparatus is truthful. Hacking believes that what justifies our belief in the pictures we construct using a microscope is not the theory according to which we are producing a truthful picture. He insists that observation is not determined by theory, and points out that people rightly believed what they saw through pre-Abbe microscopes, although they had only the most inadequate theory to back them up. So for Hacking, theory cannot be the source of our confidence that what we are seeing is the way things are. His own alternative is that what justifies our belief in what we see through microscopes is the fact that the same pattern of observations shows up when using different microscopes that employ different techniques. For instance, the low resolution electron microscope yields the same results as a high resolution light microscope. Hacking argues that it would be a preposterous coincidence if two totally different kinds of physical systems were to produce exactly the same arrangements of dots on micrographs. So the best explanation for what we see is the realist interpretation that it is really out there.

I find Hacking’s argument to the effect that justification does not require theory both significant and compelling. The idea that justification of belief needs to have a theoretical underpinning seems to be a reminder of the intellectualist tradition that associates the activities of the mind with theorizing. If we acknowledge that knowledge is not only theoretical and in the first instance includes knowing how to do things, it becomes apparent that we need an account of justification which is more concerned with what knowers do and less with what they think. Over all, I believe Hacking’s various historical examples make a good case for a pragmatic externalist epistemology.

I also like the way Hacking turns this discussion of experiments and their independence from theory into an argument for scientific realism. The main idea, which I find brilliant, is that if justification for our belief in an observation or an outcome does not depend upon theory, there is a sense in which our observations are not theory-laden and hence can be tested against experience independently of theory. That being said, I think this is just a preliminary idea and needs a much more sophisticated account to become an argument for scientific realism. Hacking’s indication that different apparatus yield similar results does not seem to be sufficient and needs to be accompanied with an account of how these results hang together with all our other scientific findings, and more importantly, how they can be put to use successfully.