In the darkness of the nearly monochrome black-gray, traces of the brush and the varying thickness of the application of the paint—from thin glazing to almost opaque—bear witness to a gestural painting process. The square, outlined with a precise line, stands in stark contrast to this, like a window in a dark, cave-like pictorial space. In the Open series from 1967, to which In Plato's Cave belongs, Motherwell reflected on the significance of the motif of the window in the history of painting. The title also refers to Plato’s allegory of the cave. Here, the Greek philosopher describes the scenario of people who, chained in a cave, can see nothing but the shadows of the things that happen behind them. They perceive this as the only reality known to them. The acquisition of this work by the Friends in 2010 was made possible by a considerable contribution from a private collector from Cologne.