Fred Dretske

(1932 - 2013)

This chapter separates cognition from perception by distinguishing between the percept—the product of pure perception which is conceptually untainted by cognitive ingredients—and a larger and more inclusive experience that is conceptually affected. It then criticizes Siegel’s view that higher-level properties are included in the content of perceptual experience, and the view that cognition affects the percept. The chapter uses a thought experiment, the ‘Goldilocks test’, to isolate cognitively unspoiled sensory core of perceptual experience. Application of the test to the perception of kinds yields the result that subjects who possess different concepts (expert and novice viewers) have the same percept. The chapter also applies the Goldilocks test to other visual cases, such as reversible figures.

It is a traditional empiricist doctrine that natural laws are universal truths. In order to overcome the obvious difficulties with this equation most empiricists qualify it by proposing to equate laws with universal truths that play a certain role, or have a certain function, within the larger scientific enterprise. This view is examined in detail and rejected; it fails to account for a variety of features that laws are acknowledged to have. An alternative view is advanced in which laws are expressed by singular statements of fact describing the relationship between universal properties and magnitudes.