Review of J.R.Lucas's 'The Future'
Percival (Philip)
Source: Mind, Vol. 100, No. 1, Jan., 1991, pp. 157-161
Paper - Abstract

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  1. Frege held that the truth-values of thoughts are temporally invariant, a semantic thesis having metaphysical expression in the notion of a "block-universe" according to which the facts don't change over time and the future, though perhaps more opaque epistemologically, is no less real than the past. An opening chapter sketches reasons, a felt need to avoid fatalism being prominent, for rejecting this view in favour of an "open" future whereby a (contingent) proposition concerning the future lacks a truth-value until the time it concerns becomes present. But Lucas's main aim is to develop a semantics (chs. 2, 4, 8-9) and logic (chs. 5-6) with which to defend an open future against both the arguments discussed by Aristotle in De Interpretatione (ch. 7) and theological determinism (ch. 3). Lucas's secondary aims amount to a "modal1 derivation" of some of time's structural features from the supposition that times are "standpoints" from which propositions can have different modal2 status (ch. 10), and a defence of the theological consequences of in some sense denying, as he argues we must if theological determinism is to be resisted, God's omniscience (ch. 11).
  2. I will focus on his main aim, which involves three fundamental ideas.
    • First, an application of Reichenbach's analysis of tense.
    • Second, a distinction between different kinds of truth, and, relatedly, a "defeasible" theory of knowledge.
    • Third, a more formal development of these ideas in a "sub-tree semantics" refining the familiar use of trees in tense logics.
    There is much to interest even a proponent of the block-universe in the first two ideas. Lucas's account of sub-tree semantics leaves much to be desired.
Final Paragraph
    Advocates of a block universe won't be persuaded by this book, nor does it aim to persuade them. Even those sympathetic to a dynamic view will find it somewhat parochial. The extensionalist programme rekindled by Davidson isn't engaged, only specialists will recognise fundamental semantic issues on which Lucas diverges from Prior, and while Lucasiewicz's anti-realism about the past gets a mention Dummett's doesn't. Nor does the backwards causation3 which would undermine the asymmetry between past and future on which Lucas relies. The book would have been improved by explicit familiarity with Evans's seminal discussion of tense-logic. Lucas says in the Preface that "I ought at this stage to go public, sharing any good ideas I have with a wider audience, and exposing my bad ones to further criticism". His timing is about right – just.


Review of "Lucas (J.R.) - The Future - An Essay on God, Temporality and Truth".

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