vehicle available to explainers and explainees! The use of graphs and mathematical symbols can reduce NL’s innate ambiguities, but (my heavy hobbyhorse) we need NL to ask, “What does your Sigma mean?”

Here’s a brief example from the new Folio Society’s divine two-volume edition of Newton’s Principia. Undoubtedly the most influential scientific treatise in history, its original Latin is a huge challenge for translators who need to combine exceptional language and mathematical skills. Archaic mathematical terms such as subsesquiplicate ratio are easily modernized, but many of Newton’s words are neologisms not found in classical Latin. The very notion of “rigorous proof” has changed since 1686, of course, so modern translations often amplify the text or change geometrical proofs into modern algebraic proofs. In Newton’s very first definition, though, we hit an intrinsic NL problem. The Latin says, “Quantitas materiae est mensura ejusdem...” For more than 300 years this was translated, “Quantity of matter is the measure of [matter that arises from its density and volume jointly].” The Folio translators (I. Bernard Cohen and Anne Whitman assisted by Julia Buzenz), however, have “Quantity of matter is a measure...” Did Sir Isaac mean “the measure” or “a measure”? Alas, Latin has that very quirk we noted in Russian: no definite or indefinite articles. ⁴

FOR is deliberately vague, but vaguely optimistic, on the practical future of QC (quantum computing). It seems part of the FOR package that our current intractability problems with classical Turing machines will be solved eventually with quantum computers or some as-yet-unknown technology. Deutsch explains the challenge as engineering “sub-microscopic systems in which informa-tion-carrying variables interact among themselves but affect their environment as little as possible.” My feeling is that FOR’s prediction made in 1997 that “more complex special-purpose quantum computers will appear in a matter of years rather than decades” is already looking overly optimistic. Cynics, though, point to at least one parallel universe where Deutsch’s prophecies have all been fulfilled. Needless to say, he has heard all such jokes before.

For a change of perspective, let’s see what the philosophers make of this reality thingy. After all, it has been their midden for many a century, long before even Plato concluded that there were universal forms and mathematical objects lurking out there, somehow “ kicking back” at those who thought about them. With the threatened emergence of TUI (tangible user interface), the more we know about sensory perception the better. I

suggest Professor Paul Coates’s The Metaphysics of Perception: Wilfrid Sellars, Perceptual Consciousness and Critical Realism (Routledge, 2007), mainly because I’ve dined with him, albeit under false pretenses. It took a while to realize that he was not the Professor Paul Coates I thought I was dining with. The latter teaches film at Aberdeen University, the former philosophy at Hertfordshire. Coates the philosopher looked blank when I told him how much I had enjoyed his books on Andrzej Wajda and Krzysztof Kieslowski. A more perceptive philosopher might have deduced the source of the error, but apparently he was unaware of his namesake and his namesake’s favorite movie-makers. I hope I’ve cleared up any confusion in your minds.

Paul’s book is a hefty $110, but you have to pay for those essay-long philosophical titles. For $42.63 via IngentaConnect, you can get the gist of his thesis from his paper “Perception and Metaphysical Scepticism” ( Proceedings of the Aristotelian Society, 1998). These ideas are more relevant to ACM readers than you might imagine, given the new extended ACM Communications. They cover the rich domain often called “mind and machine,” where rival theories of perception tussle for prominence. Are you a causalist or a disjunctivist? The causalist treats the sensory experience and the physical object perceived as distinct existences, whereas the disjunctivist claims that we “perceive physical objects directly, without being aware of any intervening states of mind, or entities such as sense data or the like” [op. cit.]. Paul Coates and I are both causalists, but it takes many pages (not to mention 45 footnotes) to clarify all the obvious objections, such as hallucinations and deviant causal chains, which occur in the disjunctivist literature. Both schools continue to look each way before crossing the road, recalling that the drivers in some countries (which shall be nameless) are daft enough to drive on the wrong side. The mantra in the UK, by the way, is “Look right, look left, then look right again.” Your directions may vary. Else, the perception of a vehicle may break the perception of your skull.

L’AFFAIRE LEDIN REDUX

You may recall my report (ACM Queue, January 2008) that George Ledin, computer science professor at Sonoma State University, California, has attracted angry objections to his courses on malware. The antivirus industry, in particular, feels that Ledin’s graduates have no business learning how viruses and other invasive nasties are constructed, nor being shown how easy it is to circumvent the defenses sold by the leading antiviral marketeers. Ledin tells me that John Aycock at Calgary University,