 In contrast with the dominant philosophical tradition that has, since Descartes, stressed the special privilege or at least high accuracy of introspective judgments about consciousness (see Section 4.1 below) many early introspective psychologists held that the introspection of currently ongoing or recently past conscious experience is difficult and prone to error if the introspective observer is insufficiently trained. Wundt, for example, reportedly did not credit the introspective reports of people with fewer than 50,000 trials of practice in observing their conscious experience (Boring 1953). Titchener, a leading American introspective psychologist, wrote a 1600-page introspective training manual for students, arguing that introspective observation is at least as difficult as observation in the physical sciences (Titchener 1901–1905; see also Wundt 1874 [1908]; Müller 1904; for contemporary discussions of introspective training see Varela 1996; Nahmias 2002; Schwitzgebel 2011b). This difference in optimism about untrained introspection may partly reflect differences in the types of judgments foregrounded in the two disciplines. Philosophers stressing privilege tend to focus on coarse and (seemingly) simple judgments such as “I’m having a visual experience of redness” or “I believe it’s raining”. The projects of interest to introspective psychologists often required much finer judgments—such as determining with mathematical precision whether one visual sensation has twice the “intensity” of another or determining along what dimensions emotional experience can vary.