She carried on reading – now truly ignoring me; all the self-consciousness and hostility had vanished. I felt a wave of relief wash over me: between us, we’d probably just saved the documentary. Her reaction to the cults had to be dealt with, but she had a right to express it more diplomatically. It was a simple, obvious compromise; I only wished I’d thought of it sooner.

I peeked at Mosala’s notepad while she read (without recording). She invoked some kind of software assistant every time she came to an equation: windows blossomed on the screen, full of algebraic cross-checking and detailed analysis of the links between the steps in Wu’s argument. I wondered if I would have been able to make better sense of Wu’s papers myself, with this kind of help. Probably not: some of the notation in the “explanatory” windows looked even more cryptic to me than that of the original text.

I could follow, in the broadest qualitative terms, most of the issues being discussed at the conference – but Mosala, with a little computerized help, could clearly penetrate right down to the level where the mathematics either survived rigorous scrutiny, or fell apart. No seductive rhetoric, no persuasive metaphors, no appeals to intuition: just a sequence of equations where each one did or did not lead inexorably to the next. Passing this inspection wasn’t proof of anything, of course; an immaculate chain of reasoning led to nothing but an elegant fantasy, if the premises were, physically, wrong. It was crucial to be able to test the connections themselves, though, to check every strand in the web of logic which bound two possibilities together.

The way I saw it, every theory and its logical consequences – every set of general laws, and the specific possibilities they dictated – formed an indivisible whole. Newton’s universal laws of motion and gravity, Kepler’s idealized elliptical orbits, and any number of particular (pre-Einsteinian) models of the solar system, were all part of the same fabric of ideas, the same tightly knit layer of reasoning. None of which had turned out to be entirely correct, so the whole layer of Newtonian cosmology had been peeled away (fingernails slipped under the unraveling corner where velocities approached the speed of light) in search of something deeper … and the same thing had happened half a dozen times since. The trick was to know precisely what constituted each layer, to prize away each interlinked set of falsified ideas and failed predictions, no more and no less … until a layer was reached which was seamless, self-consistent – and which fit every available observation of the real world.