What is commensurability in philosophy of science?

In the philosophy of science, commensurability refers to the idea that different scientific theories or paradigms can be compared and evaluated in a meaningful way. It concerns the compatibility and mutual intelligibility of theories, particularly when they address the same phenomena or questions. A key aspect of commensurability is whether there are shared standards, concepts, or measurements that allow for a direct comparison between competing theories. The concept was notably discussed by philosophers like Thomas Kuhn, who argued that when scientific revolutions occur, often the new paradigm is incommensurable with the old one. This means that the two paradigms operate with different conceptual frameworks and may not share the same terms or criteria for evaluating theories, making direct comparison difficult or impossible in some respects. Key points related to commensurability in the philosophy of science include: 1. **Conceptual Differences**: Different theories may use different terminology, frameworks, and assumptions, which can complicate direct comparison. 2. **Measurement and Standards**: Theories may also differ in their methods of measurement and the standards they use for validation, further complicating how they can be compared. 3. **Translation Problems**: Incommensurability suggests that translating concepts from one theory to another may not preserve meaning, leading to challenges in understanding and evaluating the theories in relation to one another. Overall, commensurability is central to discussions about scientific progress, theory change, and the nature of scientific understanding, as it influences how scientists communicate and assess competing explanations of the same phenomena.