Where substance is central, art is invalidated at points where substance is unknowable.

Piero Manzoni offered Merde d’Artiste in little labeled cans. Decades later one can burst open because they contain tomato paste, rather than the titular merde, and the paste in that one unlucky can had begun to rot.

Damien Hirst’sThe Physical Impossibility of Death in the Mind of Someone Living contains a real shark, held in place in a tank of preservative. We know the shark is real because periodically it needs to be replaced, since its flesh very slowly decays in spite of its surroundings. But, if Manzoni taught us anything, it’s that the absolute reality of the shark is unimportant to the work. All it needs to be is completely believable. A seamlessly realistic dead shark, say one made by Hollywood special effects artists, might have had the same effect, and would never have needed replacing.

Richard Serra sculptures weigh hundreds of tons, and cost millions simply to relocate. But couldn’t they be crafted using lighter materials, fabricated to look and behave like COR-TEN steel in ways no observer could ever deduce?

Wolfgang Laib produced large, glowing rectangles of pollen on museum floors. Even using a vacuum cleaner and extracting pollen for example from certain kinds of evergreen at just the right moment of the year, simply collecting such vast amounts of pollen, then sifting every tiny impurity out of it, sounds like a job requiring many hands, sparkling-clean facilities, and lots of time. Kudos to the artist for this accomplishment. But how can most museum visitors know that these beautiful golden rectangles are in fact made from pollen? Couldn’t visually identical artworks be fashioned from a carefully crafted pollen-like substance?

I’m not questioning for a minute the authenticity of these artworks, or the authenticity of any other conceptual artworks where substance is key. Artists in my experience don’t want their work to hinge on falsehoods, even where it would be easier and less expensive to resort to them.

But in this small segment of artworks, Manzoni showed us that another element comes into play, an element we hand over to perfect strangers without thinking once we pass through the gates of major arts institutions: trust.

Trust is not only required to appreciate these particular artworks, it’s central. Trust, and how we deploy it in institutional settings, becomes subject. Whatever importance the materials themselves pose must compete with and be shaped by the factor of trust.