Alasdair Richmond

Between Abduction and the Deep Blue Sea

Stathis Psillos and James Ladyman et al. have recently joined battle over Bas van Fraassen’s account of abduction and inference to the best explana-tion (IBE), and while van Fraassen makes many interesting criticisms, Psillos has had the best of the exchange. In part I of this paper I aim to extend Psillos’ criticisms by suggesting that van Fraassen‘s critique of IBE is at odds, not only with The Scientific Image but also with his later work. Part II uses some of van Fraassen‘s ideas to suggest a third way between realist IBE and outright abductive scepticism.

New Interpretations of Berkeley's Thought

practical philosophy, Hobbes’s own attempts to establish unimpeachable definitions would have been grist for this mill. Again, Leibniz’s philosophy of substance might appear less enigmatic when viewed against the ‘Latin pluralist’ interpretation of Aristotle adopted by the Lutheran scholars at Wittenberg, on which he would have cut his teeth. While Garber quotes Eustachius a Sancto Paulo’s textbook definition of primary matter as pure potentiality (346), Jacopo Zabarella, Julius Caesar Scaliger and Daniel Sennert regarded primary matter as real, though of indeterminate extension in the absence of form. This seems relevant to Leibniz’s own position, as does their doctrine that a substance (with its own dominant form) contains within it other substances or subordinate forms. Nevertheless, had Garber included so much historical detail this would have been a different kind of book, and perhaps not such a readable one. As it is, he strikes an admirable balance between close textual exegesis and an eye to the wider context. His writing is always engaging, well argued and provocative, and written with humility and a very generous spirit. It stands as a fitting testament to Garber’s decades-long engagement with the profound, but enigmatic, philosophy of Leibniz.

Time travel, hyperspace and Cheshire Cats

H. G. Wells’ Time Traveller inhabits uniform Newtonian time. Where relativistic/quantum travelers into the past follow spacetime curvatures, past-bound Wellsians must reverse their direction of travel relative to absolute time. William Grey and Robin Le Poidevin claim reversing Wellsians must overlap with themselves or fade away piecemeal like the Cheshire Cat. Self-overlap is physically impossible but ‘Cheshire Cat’ fades destroy Wellsians’ causal continuity and breed bizarre fusions of traveler-stages with opposed time-directions. However, Wellsians who rotate in higher-dimensional space can reverse temporal direction without self-overlap, Cheshire Cats or mereological monstrosities. Alas, hyper-rotation in Newtonian space poses dynamic and biological problems, (e.g. gravitational/electrostatic singularities and catastrophic blood-loss). Controllable and survivable Wellsian travel needs topologically-variable spaces. Newtonian space, not Newtonian time, is Wellsians’ real enemy.

Apocalypse Now Does The Matrix: Anthropic adventures from doomsday to simulation

Following on from Nick Bostroms discussion of the Doomsday argument, Alasdair Richmond considers how anthropic reasoning can lead from Doomsday to some odd conclusions about computation and our place in reality.