The key aspects of representation through measurement are:
- Measurement tells us what things look like (from a specified vantage point), rather than what they are like.
- Measurement involves selective perspectival input.
This view, which I will refer to as the ‘perspectival view,' is informative for analyzing scientific practice. It accounts for the imperfections and limitations of our representational activities while grounding a certain kind of objectivity. The phenomena are presumed to remain stable, even if our theories and practices may vary in successfully representing those phenomena. This is the basis for the appearance-reality distinction discussed in ‘Explanation and Illusion’. However, the perspectival view of measurement places too much focus on the outcome of passive representation, and not enough on the process of measurement.
Van Fraassen is wrong to use perspectival art as an analogy to measurement. Taking a perspective is a passive activity. Much of measurement is not passive. It is messy in terms of the type of interaction that takes place. And, a theory of measurement should account for this interactivity.
Here’s a simple example to bring our attention to measurement interactivity:
How do you measure the boiling point of water? You stick a thermometer in the sample, and, get a reading. This seems simple and representational: the value on the thermometer represents the quantity of temperature. But this perspectival story leaves out the interaction involved in the measurement process.
According to Hasok Chang (2004), the history of standardizing fixed points in thermometry is a history of “manufacturing” fixed points. The point at which water boils depends on the material conditions within our measurement set-ups. Initially it was discovered that boiling point varies with differences in atmospheric pressure (2004, 15). Additionally, the presence of dissolved air in water produced ebulliation-like phenomena at 101.9 degrees C (2004, 19). However, purged water (water without dissolved air) was measured to behave in a phenomenologically similar manner at much higher temperatures (as high as 140 degrees C). According to Chang, scientists began to focus on samples of water without dissolved air (2004, 16-19). Chang presents anecdote about how De Luc walked, slept, ate, etc., for 4 weeks straight all while shaking a tube of water to purge it of the dissolved air. De Luc’s dedication to manipulating the conditions of measurement serves as a good illustration of the care with which the measurement interactions have to be chosen in order to have a stable, reproducible phenomenon. It also illustrates how sensitive the phenomenon is to the interaction between conditions of the measurement set-up.
Now, for the difficult philosophical question: Is this type of measurement representational, or, is it productive? In each of the measurement set-ups, the boiling point is taking shape with the measurement conditions. In other words, the set-up provides the conditions for the production (and re-production) of the phenomenon. This type of language doesn’t have to “sound” quantum mechanic-y or constructivist. We do not have to discuss a pot of water boiling in the forest. In fact, we need not say anything about pre-measurement values and post-measurement results. All we have to focus on is that the interaction of the conditions for measurement matter to the production of the phenomenon. In simple terms, change the conditions, change the phenomenon. Whether you choose to remain a representationalist or a productivist, one thing we have to consider is that much of the measurement process occurs within the measurement set-up and execution. The final representational step, the measurement outcome, is a small slice of the process. A robust theory of measurement should account for the interactions in this process.
While we’re doing some revision, let’s try out a more adequate art analogy for measurement—one that focuses on interaction rather than passive perspective. The art process of Jackson Pollock is a good starting point.
Pollock numbered his paintings so that people would look at them without searching for representational elements in the names of his paintings (Karmel and Varnedoe 1999). For Pollock, the work of art is not a representation of a phenomenon (1999, 68-69). Rather, it is the phenomenon, which is produced by the interactions that take place in the painting set-up (1999, 99). Pollock was resistant to representation in art. He was also resistant to the view that artists should paint things “out in nature”: “When asked whether he painted from nature, Pollock replied: “I am nature”” (1999, 253). Pollock’s painting set-up and the interaction that occurred within this set-up can be summarized as follows: First, paint was carefully selected to have the proper viscosity. Pollock used gloss enamel paint rather than oil-based paint. The paint was sometimes diluted to have little textural effect, and at other times thickened. He used sticks, worn out brushes, and basting devices that looked like giant fountain pens.
Chang, Hasok. (2004). Inventing Temperature. Oxford: Oxford University Press.
Karmel, Pepe, & Varnedoe, K. (1999). Jackson Pollock: interviews, articles, and reviews. New York:Museum of Modern Art : Distributed by H.N. Abrams.
van Fraassen, B. C. (2009). Scientific representation: Paradoxes of perspective. Oxford: Oxford University Press.