Lucid dreaming provides a test case for theories of dreaming. For example, whether or not “loss of self-reflective awareness” is characteristic of dreaming, it is not necessary to dreaming. The fact that lucid dreamers can remember to perform predetermined actions and signal to the laboratory allows them to mark the exact time of particular dream events, allowing experiments to establish precise correlations between physiology and subjective reports, and enabling the methodical testing of hypotheses.

[Hobson et al.; Solms]