"The look in the picture does seem to be meant to be complicated, as if it issued from some process of inquiry; but it is also meant to be businesslike. There may be some epistemological anxiety about, but we are surely not supposed to take the subject as overwhelmed by it: his look is poised, cool and craftsmanlike, the look of a professional. (These last are class attributes as well as professional ones, and the look of self-portraiture is shot through with signs of class and gender. It is the look of mastery: of containment, detachment, distance, sang froid, self possession....) Perhaps in the end, for all its coolness, this is a look that intends to break through the surface to some truth within. But we cannot be sure, and it is part of self-portraiture that we should not be; maybe the point or effect of the mirror is to let the look deal strictly with appearances. The look in self-portraiture never stops oscillating between these two possibilities, these two kinds of reading." T. J.Clark The Look of Self-portraiture
Background: Painted in prison in 1794, immediately after the fall of the Robespierre regime. David might well have faced a death sentence but was spared.