Measuring the mental.

Abstract Many philosophers have argued that the subjective character of conscious experience results in a fundamental deficit of third-person (henceforth: extrospective) access to first-person experience. By comparing extrospective measurement techniques with measurement techniques in the natural sciences, we will argue that extrospective methods suffer from no such deficit. After a rejection of some principled objections against extrospective methods, a historical comparison with the development of measurement techniques in the natural sciences will show that extrospective measuring methods are still in an early stage of development. However, they can be significantly improved by way of a bootstrapping strategy, similar to that which has proven successful in the development of physical measurement techniques. One reason to expect such improvement is the availability of multiple sources of evidence, which should allow for substantial advances in extrospective measurement techniques. Finally, we will discuss new developments in pain measurement in order to show that the bootstrapping strategy is already bearing fruit.