Jeremy Deller is walking rapidly through the English painting room at the National Gallery, past the aristocratic portraits by Thomas Gainsborough and Sir Joshua Reynolds, before he settles in front of a William Hogarth set called Marriage A-la-Mode (1743-45), which charts the ups and downs — mostly downs — of an ill-matched society couple. It’s all drunkenness, party aftermaths, slumped syphilitic society figures, diseased faces, the buttocks of an adulterous man fleeing out of a window, a disgraced woman downing laudanum. “This,” says Deller, gesturing to the other paintings, “is how we want to be seen, but Hogarth paints people as they really are.”