Question 1: Kuhn does not think that scientific theory choice is determined solely by evidence. Why not? Why can’t evidence force theory change, and what other considerations get involved?
Scientific theory choice is determined by several factors rather than just the presence or absence of evidence. These factors that determine the choice of a theory are according to Kuhn, an influence of the community of scientists rather than a decision of a single scientist. Kuhn argues that in the presence of two theories that do explain a similar scenario, the choice of the more virtuous theory is down to a group of practitioners designing several weighting preferences upon which the virtuous theory can be decided. The strength of evidence is not in this case considered as a factor of choice of a theory. According to Kuhn, factors such as the internal and external consistency of a theory, empirical accuracy of the theory, scope, fertility and simplicity of the theory are used as the standard set of theoretical virtues upon which the most virtuous theory is decided. The choice is based upon the merit score of each theory on not one but all of the set of virtues. His most catching phrase that at times sends the minds of most scientists into surprise is when he suggests that “Normal science does not aim at novelties of fact or theory and, when successful, finds none (pg.52)”
The above virtues are therefore expected to form an interplay that will allow a theory which will generally be perceived as most virtuous. A theory say 1 cab be perceived as simpler than a theory 2 but this alone cannot be used to classify theory 1 as the most virtuous. Similarly, theory 2 can be perceived as the one with a greater scope and empirical accuracy but these alone cannot be used to classify this theory as the most virtuous. In order for any of the theories to outdo the other, it should be able to score highly across all merits in the score card drawn from the set of standards being used. This is a task performed by a community or team of practitioners. There is no limit of choice for any individual practitioner or scientist during the session when the ‘choice’ is about to be made. Each individual scientist is independent to give their own view of a theory in relation to the virtues (pg.26).
This implies that the commonality of the ‘choice’ will be reached only through the shelving of individual choices and adopting a common score card. However, Kuhn notes that the choice of a theory at the community of scientists’ level is based more on the values or virtuous rather than on the rules and algorithms that form the basis of that particular theory. At individual level however, the choice of the best theory is determined by evidence. This is foregone at the community level since it is quite hard for all members of the community if scientists to come to an agreement based on evidence. Thus the use of values or virtuous to make a theory acceptable to all or at least to the majority is seen as the last resort. Compromises are thus made on the strength of evidence used to formulate a theory; but according to Kuhn, this is an essentiality rather than a matter of choice (pg. 73).
As a matter of essentiality, Kuhn’s suggestion seems to build an argument that the choice is based on the problem-solving-capacity of the framework or theory. In this case, the ability of the theory to solve a real-life problem consistently over time becomes more of a dictator of the choice. This means that a paradigm that stands the test of the times. Kuhn idea is that not all individual scientists will be of the decision that a particular theory is the best in solving a problem. There are other social mechanisms through which the ‘choice’ will be arrived at. However, the diversity of ideas by the individuals within the community of scientists and in particular the resistance is not viewed as illogical or unscientific. It is later used to formulate other paradigms that can be applicable in new areas. Thus verification of one theory over another is a matter of picking the most viable rather than dismissing all other alternatives. “Verification is like natural selection: it picks out the most viable among the actual alternatives in a particular historical situation (pg.149)”. This verification is essentially a last resort to a persistent problem.
In some instances, a theory can be overruled by another even on the basis of aesthetics. This is in cases where a new paradigm is argued and its rules and algorithms are capable of solving a problem that has previously been solved by an older paradigm or theory. When the new theory suggestively becomes more aesthetic, scientists are forced to abandon the older theory. “These are the arguments, rarely made entirely explicit, that appeal to the individual’s sense of the appropriate or the aesthetic-the new theory is said to ‘neater,’ ‘more suitable,’ or ‘simpler’ than the old. Probably such arguments are less effective in the sciences than in mathematics. Nevertheless, the importance of aesthetic considerations can sometimes be decisive. (Pg.149)”
Question 2: Discuss critically the argument presented in question 1.
Kuhn’s argument is substantially biased towards reaching for a final choice. His arguments seem to dwell more on the importance of reaching for a choice that will solve a particular problem. The methodology of ,making this choice, according to Kuhn does not necessarily need be scientific or evidence based as long as there is a unanimous decision by the community of scientists that a particular theory is the most virtuous among alternatives. His argument seems to forego the importance of evidence in the final decision making. He, in particular argues that “crisis alone is not enough. There must also be a basis, though it need be neither rational nor ultimately correct, for faith in the particular candidate chosen (pg. 158)”. This idea suggests that the choice of the theory should be focused on promise of future success. This would be ultimately be a biased decision and would be a way of undermining the effort placed on contemporary theories that do not make it on the final huddle.
Scientists should choose a theory based experimentation rather than on theory choice because according to Kuhn a theory is depends on accuracy and simplicity this makes the theory not really effective since the selection of the theory is done by a community of scientists who base their argument on their logical views to select between alternative theories. Whereas the scientific scope of view is that an individual can solely choose a theory based experimentation for example experimental biology which is cost effective. Experimentation also leads to modification and improvement on certain aspects and branches of science to be able to match the advancements in technology other than theory choice .Theory choice may be biased since the individuals choice could be based on their preferences.
The use of values as metrics to determine the most virtuous theory seems to undermine the general perception that science is an evidence-based field in which assumptions are not tolerated. This leads us believe that Kuhn is trying to create a balance between positivism an realism and one that proves hard to accomplish (pg.65).
Kuhn, Thomas S. The Structure of Scientific Revolutions. 3rd ed. Chicago, IL: University of Chicago Press, 1996. Print.