There's a weird thing about acting. It should be the most shaded and amorphous of the arts, and assessment of its quality among the most subjective of judgements. But the opposite is the case. Art, plays and especially films and novels can be assessed as worthless or genius even within a narrow set of agreed values -- great acting is a small miracle, but bad acting is bad acting; a competent performance, well, you can just feel it clicking into place. At the higher mid-level reaches that becomes dependent on the approach you prefer: Kenneth Branagh in Mary Shelley's Frankenstein is either masterful or, well, unlikely to gain a halal certificate.

And then there are the performances that break the frame altogether, reach into a different register of being, and show most acting to be contained within a set of conventional gestures. The most recent of these, to have a wide audience, was Daniel Day-Lewis' portrayal of Abraham Lincoln, which, well, it's very hard to describe. That's the thing about acting; it is only striking to the degree it slips away from language, evades characterisation, in anything other than the most descriptive fashion. Try to read theatre criticism from a half-century ago, say, and try and reassemble a picture of the performance. "Thalyssia Kischmitz gave us a brittle, wide-ranging Medea, with an underlying air of menace." What does that mean? It could mean anyone of half a dozen performances, all contradicting one another, and reassembling some reliable picture of it is impossible. It means nothing, or next to it, and a vast amount of performance-oriented theatre criticism is bogus, filler, like a sports writing.