 Descartes’ remarks about the discontinuous and ad hoc nature of many dreams are backed up by empirical work on dream bizarreness (see Hobson 1988; Revonsuo &amp; Salmivalli 1995). Still, many of his critics were not convinced this helped his case against the skeptic. Even if Descartes’ revised phenomenological description characterizes most dreams, one might occasionally merely dream of successfully performing the test (Hobbes 1641), and in some dreams, one might seem to have a clear and distinct idea but this impression is false (Bourdin 1641). Both the coherence test and the criterion of clarity and distinctness would then be unreliable.