How do causal chains and social practices help fix the reference of scientific terms according to Putnam?

According to Hilary Putnam, the reference of scientific terms is not fixed by mental images, definitions, or descriptions, which he argued are insufficient to anchor language to reality. Instead, he proposed that reference is established through external factors, a view central to his semantic externalism.

Putnam argued that the connection between a scientific term and its referent is maintained by:

• Causal Chains: The use of a term is linked to an entity through a historical chain of prior uses, tracing back to an initial contact or identification of the object.
• Social Practices: The reference is anchored by communal activities such as pointing, moving, and weighing the substances or entities in question.

By grounding reference in these external, objective interactions rather than internal mental states, Putnam demonstrated that theories from different scientific paradigms can refer to the same entities. This allows for continuity in scientific reference even when theoretical definitions or descriptions change, thereby defeating the relativist argument that such theories are incommensurable.1