Isham, C.J. and J.C. Polkinghorne. “The Debate over the Block Universe."

Is ours a world of timeless being (the “block universe”) or of flowing time and true becoming? The current debate over the block universe, represented in the essay by Chris Isham and John Polkinghorne, brings together scientific, philosophical and theological arguments in a tightly-knit, interwoven pattern.

Proponents of the block universe appeal to special and general relativity to support a timeless view in which all spacetime events have equal ontological status. The finite speed of light, the light cone structure, and the downfall of universal simultaneity and with it the physical status of “flowing time” in special relativity result in a heightened tendency to ontologize spacetime. The additional arbitrariness in the choice of time coordinates in general relativity makes flowing time physically meaningless. Thus no fundamental meaning can be ascribed to the “present” as the moving barrier with the kind of unique and universal significance needed to unequivocally distinguish “past” from “future.” Instead the flowing present is a mental construct, and four-dimensional spacetime is an “eternally existing” structure. God may know the temporality of events as experienced subjectively by creatures, but God cannot act temporally, since flowing time has no fundamental meaning in nature. Theologians must accept the Boethian and even gnostic implications of the block universe.

Opponents of the block universe begin by distinguishing between kinematics and dynamics. Special relativity imposes only kinematic constraints on the structure of spacetime. The dynamics of quantum physics and chaos theory encourages a view of nature as open and temporal, thus allowing for both human and divine agency. The problem of the lack of universal simultaneity is lessened since simultaneity is an a posteriori construct. Philosophically disposed to critical realism, opponents are wary of the incipient reductionism of the block view. They resist the Boethian implications of relativity, and argue instead that divine omnipresence must be redefined in terms of a special frame of reference, perhaps one provided by the cosmic background radiation. God’s knowledge of spacetime events in terms of this frame of reference will be constrained by both the world’s causal sequence and the distinction between past and future. Similarly God’s actions will be consistent with relativity theory.

In the end, is the debate merely philosophical or could it actually have scientific consequences? Proponents of the block universe challenge their opponents to decide between a mere reinterpretation of the existing theories of physics and the much stronger claim that these theories should be changed. If forthcoming, such changes ought to be testable empirically and would constitute a major achievement in the debate over time. Proponents also point to additional complexities in the debate, such as the problem of giving a realist interpretation of quantum physics. These problems become even more acute when dealing with quantum cosmology, making an atemporal interpretation almost inevitable. They do not object to positing that God experiences the world through a special frame of reference or that God is aware of the experience of temporality of living creatures. However they find it hard to understand how God’s action on the world can respect the causal constraints on such action entailed by special relativity.

Email link | Printer-friendly | Feedback | Contributed by: CTNS/Vatican Observatory