During its short formal history, psychology has proclaimed itself to be a science, though this claim has sometimes been disputed (as we’ll see) and what goes after the intro text definition “Psychology is the science of ….” has changed. However, it’s rarely the case (outside Division 24 types) that psychologists tackle the question of what science is and how it works. There’s a huge literature on this (it’s called philosophy of science), but as Thomas Kuhn observed about sciences in general, scientists consult this literature only during periods of doubt and crisis. This literature is the focus of the first 2 weeks’ classes, though I try to tame it by focussing on one important question: What is scientific explanation? Thus we also will ask, can psychology give scientific explanations of the same type given in other sciences? Should it?
Afterthoughts on class of August 21. On our first day, I took up the question of scientific explanation, and covered the most traditional way of treating it, associated with positivism and logical positivism. The positivist movement is of great importance in philosophy of science, because it basically created the field. Positivists saw science as a uniquely (in the strong sense) successful human institution, and strove to distill the essence of science into a content-free set of methods that could be applied to any topic whatsoever, from the movements of the planets to the question of god’s existence. As it did so, positivism began to influence the practice of science, especially those sciences, such as psychology, that were uncertain of their status as sciences (we’ll get to this historical part later).
Positivists proposed a very precise definition of scientific explanation, the deductive-nomological model, that I covered in the first lecture. Critical to the the D-N model are these ideas: laws of nature, explanation as deduction, and explanation as prediction.
Forethoughts. In the next class, we will consider criticisms of the D-N model and alternatives to it, most importantly the causal approach and the semantic conception of theories. One thing to do before class is to think about the term “model” as you have encountered it in psychology and the use of the term “model” in the economics paper I have asked you to read. Of course, that paper’s authors are writing for fellow economists, so their definition is implicit (though, as we’ll see, closer to the formal meaning in philosophy of science) and thus hard to grasp. But I hope the exercise in encountering a mysterious, even alien, scientific, culture, will help in achieving one of my major goals for the course: Seeing psychology from the outside.