“Why Do Evolutionary Biologists Formulate A Priori Laws Rather Than Empirical Laws?”
By Mehmet Elgin (Muğla University)
Date: Friday, 31 March
Abstract: Unlike any branch of physics, evolutionary biology is peppered with a priori mathematical models. It is important to explain why this is the case. I will argue that when we examine the principle of natural selection carefully, we see that this law relates fitness to gene frequencies. Fitness appealed to in this law is stripped away from any physical or biological details and it represents a mere mathematical value. When we relate this value to gene frequencies, we are relating two mathematical values. As a result we end up with a priori laws. I will then provide a more general argument for this fact: Fitness is a genuine multiply realizable property. Only laws that can be formulated about genuinely multiply realizable states are a priori laws. Therefore, only laws that can be formulated about fitness are a priori laws. I will finally argue that such a priori laws in evolutionary biology have very important functions: They are essential for us to be able to formulate empirically testable causal hypotheses about the evolution of specific populations and they are also indispensible in developing causal explanations systematically.