…Plato was well aware of the fact which Aristotle urges as a flaw in his theory, namely that it is impossible for all his figures to fill up space with entire continuity. In the structure of air and water there must be minute interstices of void; there must also be a certain amount of void for the reason that, the universe being a sphere it is impossible for rectilinear figures exactly to fill it up.

– John Cook Wilson: ‘On the Interpretation of Plato’s Timaeus’, 1889

Mr. Reinhardt is a puzzler. His tenacity over so long a period in the service of an increasingly tight premise is admirable. But the logical application of this premise (apparently, that by infinitely painstaking selection and discarding an artist may extract an irreducible essence from color and geometry, the bases of painting) has led him, , as it did not lead Mondrian, close to the discovery that essence but a void may lie at the end of his search.

– John Canaday: ‘Art, Running the Gamut’, New York Times, 21 October 1960

John Canaday, art critic of The New York Times, writing in 1960 of Mr. Reinhardt’s search for severe purity, said it “has led him, as it did not lead Mondrian, close to the discovery that essence but a void may lie at the end of his search.

– New York Times: ‘Ad Reinhardt, Painter, is Dead’, 1 September 1967