Aristotle's lesser-read treatise on sleep, *De Somno et Vigilia*, makes a claim that sounds peripheral until you sit with it: the transition between waking and sleeping is where the body's internal disturbances surface most legibly — fevers announce themselves, strange pains clarify, mood shifts that were masked by the day's activity become unmistakable. He treated the threshold state not as an absence of consciousness but as a diagnostic window. What's striking is how this maps onto something Paul Ekman documented empirically in the 1970s: the face, in micro-expressions lasting under a quarter of a second, reveals affect that the voluntary presentation immediately suppresses. Different traditions, same structural claim — concealment costs energy, and where energy flags, truth leaks through. For clinicians, this suggests a specific and underused orientation: the transitions in a clinical encounter — the moment before the patient has composed their presenting narrative, the pause after an unexpected question, the instant of standing to leave — may carry more signal than the prepared account at the center of the consultation. The middle of the story is often the most managed part.

In your last week of clinical encounters, what did a patient's transition moment — arriving, pausing, reaching for the door — tell you that their words didn't?

Drawing from Aristotelian philosophy synthesized with empirical psychology of affect — Aristotle (De Somno et Vigilia, c. 350 BCE) synthesized with Paul Ekman (Emotions Revealed, 2003; micro-expression research, 1970s)