Contributed by David Carrier / Raphael Rubinstein, who co-curated “Schema: World as Diagram” at Marlborough with Heather Cause Rubinstein, observes in the catalogue that diagrams are important because they sometimes have much greater explanatory power then words. Rather than tell someone directions, which can be tricky, it might be better to draw a diagram. With work by more than fifty artists on two floors, “Schema” presents an extraordinarily full history of this form, reflecting how a diverse range of artists have collectively created and responded to an aesthetic tradition. Using diagrams, of course, is no guarantee of making sense. Indeed, in its preoccupation with thorough description as opposed to subtle evocation, it might suggest lonely, ruminative souls without audiences. But diagrams can also be a rich way of communicating, and this show focuses on that capacity.