In his famous chapter of The Order of Things, Foucault examines the painting Las Meninas (The Maids of Honor) by the Spanish painter Diego Valasquez. The painting is a representation of representation. It depicts represents the artist himself at work on a large canvas, only the back of which is visible to us, the observers. In the front center, and the de facto focal point is the princess Margarita, accompanied by her maids. Also in view are a dwarf, a jester, a dog, courtiers. To find the purported subject of the painting we must look into the mirror hung in the background where one catches a glimpse of the dim reflection of the faces of the King and Queen, Philip IV of Spain and his wife Mariana, who are being painted by Valasquez. Aside from this reflected image, the King and Queen are not visible to us.

Thus the absent subject (Philip and Mariana) and the real observer (us) are located in the same position. One might say that we, as the observers (subject), and the observed (object), take part in a ceaseless exchange, ever reversing roles. When we look at the painting, it looks back at us. However, is it looking at us, or are we standing in the place of the King and Queen who are reflected in the mirror on the opposite wall?

The value of Valasquez's painting for Foucault lies in the fact that it introduces uncertainties in visual representation at a time when paintings were thought to be "windows onto the world." The Maids of Honour is a very early critique of the supposed power of signs to represent things-in-the-world.