We seem to be surrounded by bell curves—curves more formally known as normal distributions, or Gaussian distributions. All manner of things appear to be distributed normally: people’s heights, sizes of snowflakes, errors in measurements, lifetimes of lightbulbs, IQ scores, weights of loaves of bread, and so on. Lyon argues that the standard explanation for why such quantities are normally distributed, which one sees throughout the sciences, is often false. The standard explanation invokes the Central Limit Theorem, and he argues that in many cases the conditions of the theorem are not satisfied. Lyon offers some alternative explanatory schemas for why a given quantity is normally distributed.
Aidan Lyon is an Assistant Professor of Philosophy at the University of Maryland, College Park. He holds a PhD in Philosophy (Australian National University) and degrees in Mathematics (BSc) and Philosophy (BA) (University of Queensland). He works mainly in philosophy of science, philosophy of probability, formal epistemology, and philosophy of mathematics, but is also interested in topics in philosophy of physics and biology. His recent work has been on understanding the notion of objective probability in various scientific theories, with a focus on classical statistical mechanics and evolutionary theory. He also works on issues surrounding judgement aggregation/consensus formation and biosecurity intelligence gathering and analysis. This work is done in collaboration with the Australian Department of Agriculture, Fisheries and Forestry (DAFF), and is supported by the Australian Centre of Excellence for Risk Analysis (ACERA).