In the 1950s–60s biochemists searched intensively for a series of high-energy molecules in the cell. Although we now believe that these molecules do not exist, biochemists claimed to have isolated or identified them on at least sixteen occasions. The episode parallels the familiar eighteenth-century case of phlogiston, in illustrating how error is not simply the loss of facts but, instead, must be actively constructed. In addition, the debates surrounding each case demonstrate how revolutionary-scale disagreement is sometimes resolved by differentiating or (...) partitioning empirical domains, rather than by replacement of one theory by another. (shrink)

There are two reasons, I claim, scientists do and should ignore standard philosophical theories of objective evidence: (1) Such theories propose concepts that are far too weak to give scientists what they want from evidence, viz., a good reason to believe a hypothesis; and (2) They provide concepts that make the evidential relationship a priori, whereas typically establishing an evidential claim requires empirical investigation.

Gilbert and Mulkay, in their paper ‘Experiments Are the Key’, present responses of scientists to questions about the development of the chemiosmotic hypothesis of energy coupling in oxidative and photophosphorylation, and infer from these responses both the meaninglessness of the concept ‘key experiment’ and the hopelessness of searching for any data as a bedrock for historical analysis. Gilbert and Mulkay's nihilism is, however, rooted in a lack of understanding of the specific scientific issues involved. A closer look at a proposed (...) ‘key experiment’ shows certain obvious characteristics that could be criteria for a ‘key experiment’ moreover, the actual scientific response to that experiment demonstrates its pivotal role in the development of the field. Instead of demonstrating the lack of empirical bases for scientific judgment, Gilbert and Mulkay demonstrate the necessity for identifying the crucial issues and pursuing them, in questioning the scientists as well as in examining other sources. (shrink)

There are two reasons, I claim, scientists do and should ignore standard philosophical theories of objective evidence: Such theories propose concepts that are far too weak to give scientists what they want from evidence, viz., a good reason to believe a hypothesis; and They provide concepts that make the evidential relationship a priori, whereas typically establishing an evidential claim requires empirical investigation.