Craig, William Lane. The Tenseless Theory of Time: A Critical Examination.

Copan, Paul

Synthese Library: Studies in Epistemology, Logic, Methodology, and Philosophy of Science, vol. 294. Dordrecht: Kluwer Academic Publishers, 2000. x + 256 pp. Cloth, $103.00 -- This companion volume to philosopher (and A-theorist) William Craig's Tensed Theory of Time is an excellent exposition and critique of the arguments for a tenseless (B-theory) of time as well as a presentation of arguments against it; thus, in light of the Tensed Theory volume, Craig sees an A-theoretic (tensed) understanding of time vindicated. The present volume is, again, divided into two parts: "Arguments for a B-Theory of Time" (chapters 1-5 deal with the Special Theory of Relativity [SR], and chapter 6 addresses the alleged mind-dependence of temporal becoming) and "Arguments Against a B-Theory of Time" (chapters 7-9 deal with philosophical objections to the B-theory and chapter 10 with theological objections to it). Craig's meticulously researched and well-reasoned book exhibits an impressive grasp of the physics of relativity and its various interpretations.

In chapter 1 ("SR and the B-Theory") examines the presumption that SR demands a B-theoretical understanding of time ("all events in spacetime are equally real"), thus "excluding the objective reality of tense and temporal becoming" (p. 3). Craig argues that the various bizarre and counterintuitive scenarios brought on by the SR (Twin Paradox, length contraction of rods in motion, clock retardation) must be critically examined. In the first place, much depends upon which interpretation of SR is adopted: the Einsteinian relativity interpretation (which is a theoretical construct rather than an ontology or depiction of reality, leading to a denial of any objective frame of reference and simultaneity and affirming a pluralist ontology) or the Minkowskian spacetime interpretation (in which a shared, objective unified reality exists independently of observers or reference frames). The former is counterintuitive and fantastic as well as explanatorily deficient. What then of the alleged rod-length contraction and other such examples to undercut the notion of simultaneity and any objective reference point? The spacetime interpretation, which would vindicate a B-theory, views an unchanging, four-dimensional object "from different angles" or varying coordinates (p. 25). Craig is convinced, though, that the SR poses no challenge for an A-theory (and he hints at this in bringing up the Lorentzian model), but the very underlying assumptions of SR must be scrutinized.

Chapter 2 ("Time and Its Measures") goes back to Newton's important (but often ignored) distinction between metaphysical/absolute time (and space) and relative time (and space). Newton's theistically-inspired outlook--in which God is of everlasting duration and is omnipresent--maintains that there exist both a metaphysical (absolute) time and a metaphysical space, which are unaffected by (relative) physical time and space and their measurements. Despite some of Newton's shortcomings (relativity theory does correct Newton's concept of physical time), his concept of metaphysical time is unaffected. In fact, it was Einstein who essentially secularized physics (p. 53), which becomes the topic of chapter 3 ("The Epistemological Foundations of SR"). Inspired by a philosophically problematic positivism (through the influence of the militantly antimetaphysical Mach as well as Poincare), Einstein stripped away Newton's metaphysical time and space, leaving only physical time and space. For Einstein, reality is "reduced to what our measurements read" (pp. 63-4), and verificationism permeates Einstein's work on relativity. His work was eagerly received by positivistic philosophers and physicists. They arbitrarily rejected anything that smacked of metaphysics--an assumption that has been shown to be incoherent and inadequate (p. 74). What the B-theorist must recognize is that the A-theorist can consistently embrace SR, but the deeper issue between the relativity and spacetime interpretations is metaphysical.

Chapter 4 ("SR's Elimination of Metaphysical Time") notes that positivism has played an essential role in SR. However, positivism is virtually universally recognized to be false. Thus, with Newton, the A-theorist is free to distinguish between physical/relative and absolute space and time. It was, in fact, positivism--not breakthroughs in modern physics--that led to the rejection of absolute simultaneity (p. 85). Chapter 5 ("The Vindication of Lorentz") argues that a neo-Lorentzian interpretation of relativity, which is harmonious with an A-theory of time, is preferable in several ways to an (often nonempirical and ad hoc) Einsteinian version. Thus the vindication of a B-theory of time in view of SR has not been shown.

Chapter 6 ("Three Arguments for the Mind Dependence of Becoming") attacks Grtinbaum's three faulty arguments against the A-theory. Grunbaum misconstrues presentness and offers what turn out to be linguistic confusions to support a B-theory. Craig argues that presentness is absolute, that past and future are relational terms anchored in what is absolutely present, that Grunbaum begs the question by ignoring the distinction between metaphysical time and physical time, and that Grunbaum wrongly assumes that events can, say, have the property of futurity (when in actual fact only presentness is a real property of events).

In chapter 7 ("The `Spatializing' of Time"), Craig discusses the tendency of B-theorists (for example, Hawking) to spatialize time, which is both unjustifiable and metaphysically incoherent. In chapter 8 ("The Incoherence of Mind-Dependence of Becoming"), Craig points out the serious dichotomy into which the B-theorist is forced by her view. Besides the potential problem of self-referential incoherence and the rejection of our properly basic experiences of temporal becoming, there is "the metaphysical dichotomy between the external, physical world and the inner life of the mind which is intolerable" (p. 177). Chapter 9 ("The Problem of Temporary Intrinsics") shows that endurantism (embraced by A-theorists) is conceptually superior to perdurantism (embraced by virtually all B-theorists); perdurantism suffers from being metaphysically counterintuitive, defying the phenomenology of personal consciousness, invalidating moral responsibility, and so forth. Chapter 10 ("Creatio ex nihilo") puts forward theological objections to the B-theory from the biblical doctrine of creation out of nothing, which affirms the universe's origination and temporal beginning (also being well supported by big bang cosmology), which is difficult to account for in the B-theorist scheme of things.

In light of Craig's Tensed Theory and Tenseless Theory volumes, he concludes that "it is the A-theory of time which must be judged to be correct. Time is tensed" (p. 221). Indeed, philosophers of time and philosophers of science--not to mention metaphysicians--are indebted to Craig and will need to interact with the remarkable and substantial case he has made.--Paul Copan, Trinity International University and RZIM.