– Do you agree with Duhem that there cannot be crucial experiments? Can you make an example?
I think there might be crucial experiments, but they do not guarantee the full description or explanation of a phenomenon. I want to give an example from my field of research (plasma catalysis). The catalytic reactions have been studied for years to increase the production rate of valuable products. Once we combine those reactions with some plasma applications, we observed an enhanced conversion of input gas flow (for example in the production of ammonia by nitrogen and hydrogen). Some thought plasma is affecting the catalytic materials, while the others believe the material is making some changes on plasma properties. Our group showed in the first experiment that there is no change in the macroscopic properties of plasma. Then, we designed an experiment with some expensive tools to see if there is any change on the catalytic material due to plasma. So, the second experiment seems so crucial to us to end the discussion on what is responsible for the enhancement. However, as I stated before, we didn’t probe the plasma in atomic level, it was a lumped study, which may cover the possible changes on plasma. In Duhem’s sense, there is no crucial experiments, but I believe an experiment might be still crucial, if its result will provide an answer to strengthen a possible explanation.
– In your opinion, what are the consequences for the rationality of science if we accept that theory choice does not work as an algorithm but it is influenced by values?
As Kuhn suggested, the choices scientists rely on are affected by objective -shared- criteria as well as subjective factors. The algorithm is the part of objective process, mostly, because it returns a result based on predefined rules. However, this algorithm also requires some input to start with, which makes ‘the scientific algorithm’ shaky. The input information may come from the previous theories or experiments, that those are possibly influenced by the tradition or even ‘the spirit of the time’, if we think of geocentric theory as an example. On the other hand, science is still reliable and rational due to its testability and fallibility (yes, I love Popper). The geocentric theory was applicable to how stones fall, how water pumps function etc., but it required a stationary Earth. Many astronomers questioned this: “Ok, we observed other planets moving around, then why our lovely Earth is stationary?”. Because, they were not able to understand the role of gravity in a way that keeping the planets in their orbits and preventing people and atmosphere to fly away, till someone called Newton proved mathematically by inventing differential calculus. Is this theory testable, even though he just showed mystical mathematical expressions? Absolutely yes! Look around! You can easily see that ocean is moving back and forth at coasts due to tidal force between Earth and Moon, exactly how Newton describes. So, that is highly possible that theory choice is a combination of values and criteria, but once we accept that point of view, we’re also framing an unshakable stage for science itself and questioning its rationality is out of game, I guess.
