Underdetermination in science: What it is and why we should care

The underdetermination of scientific theory choice by evidence is a familiar but multifaceted concept in the philosophy of science. I answer two pressing questions about underdetermination: "What is underdetermination?" and "Why should we care about underdetermination?" To answer the first question, I provide a general definition of underdetermination, identify four forms of underdetermination, and discuss major criticisms of each form. To answer the second question, I then survey two common uses of underdetermination in broader arguments against scientific realism and in support of the use of values in scientific theory choice. I conclude that philosophers should also care about underdetermination because it impacts scientists in their practice.