Continuing our exploration of eternity in open theism, and specifically the implications of Einstein’s theory of special relativity, we’ll now move on to Einstein’s theory of gravity, that is, general relativity.
The mystery of mass
Once again this is not the place for a primer on the theory of general relativity, but we’ll go through some key elements and then explore their implications for time and eternity.
Isaac Newton, in his Philosophiæ Naturalis Principia Mathematica of 1687, already observed the remarkable fact that an object’s inertial mass – how hard it is to get it moving – is the same as its gravitational mass – how heavy it is. That may sound obvious, but in Newton’s theory of gravity there’s no a priori reason why this should be so. Yet measurements have confirmed to extraordinary precision that inertial and gravitational mass are exactly the same.
For reasons of aesthetics and simplicity, if these two types of mass are always absolutely the same, most theorists would expect there to be a fundamental reason in physics for this to be the case. In other words, there’s got to be a deeper theory, and probably new physics. The frustrating fact was, though, that until 1959 there was no experimental data available to provide hints what that might be (interestingly, a similar situation exists today with regard to the Standard Model of particle physics).
Einstein was undeterred. His key insight from 1907 onward was that if gravity were in fact geometric, that is, caused by the “bending” of spacetime itself, then its effect would simply be another form of acceleration – and hence, inertial and gravitational mass would be fundamentally one and the same thing.
This is how it works. The diagram to the left gives an impression of the grid of spacetime being distorted by the presence of the earth. You can intuitively sense that if you’d drop a small ball on this grid, it would start rolling towards the earth. This is the earth’s gravitational pull mediated by the curvature of the spacetime grid.
Let me put that in more everyday terms. Why do you feel your weight pressing on the seat of your chair right now? Because, in fact, the earth’s mass is warping spacetime around you in such a way that without any force acting on you, its curvature would take you straight down through the earth’s crust and into its core (with fatal results: it’s hot down there). Fortunately, your chair is solid, as is the earth’s crust it is resting on, and the force it exerts on you serves to continually accelerate you away from this gruesome fate. That acceleration is what you are experiencing as weight. Your weight (heavy mass) is therefore just a form of acceleration (inertial mass).
In God and Einstein I, we saw that eternity conceived in such a way that God experiences the passage of time makes him (or at least, his present awareness) necessarily subject to both time and space, allowing him properties of particularity, shape and movement in creation more usually associated with the incarnation.
But the theory of general relativity now tells us that the spacetime matrix itself is subject to “bending” by gravitational forces. If God’s present is constrained in time, and therefore space, he will inevitably be impacted by its curvature. In other words, God is impacted by gravity.
Sounds peculiar? It gets worse.
Once a sufficiently great mass is concentrated in a small space, spacetime gets warped, as it were, beyond the breaking point. Its structure effectively breaks down. This singularity is surrounded by an area of such great gravitational distortion that you would need to exceed the speed of light to get away, which is fundamentally impossible. It is a “black hole“, and nothing can escape it. The boundary around this hole, the event horizon, is a place where time is stretched so thin that, to an outside observer, someone falling into the black hole seems to increasingly slow down as they near the event horizon, never actually managing to reach it (gravitational time dilation). To the falling person themselves, though, this isn’t the case. In their particular timeframe, they don’t experience any slowing down and pass the horizon in good time. You could say that, in a way, you end up falling through the event horizon at the other side of eternity.
Now try imagine in there an omnipresent God who experiences the passage of time as Rice, Pinnock et al have it. In fact, don’t try. That God does not exist. If he is subject to the passage of time, either a black hole represents a discontinuity in his presence radical enough to disrupt his unity, or he has simply no access inside an event horizon and is not omnipresent at all. You could then escape the gaze of God simply by jumping into a black hole – but make sure to pick a supermassive one, else the tidal forces would spaghettify you before you’d made your way in.
For completeness’ sake I should add that Stump and Kretzmann‘s “eternal present” does not exhibit this difficulty, but as noted before this comes at the price of introducing a concept of ET-simultaneity that appears to move problems around rather than resolve them.
It gets worse still. In addition to the fabric of spacetime admitting singularities, it is also finite.
First of all, it is finite in extent. The universe has a boundary. Not only is all the “stuff” (matter and radiation) in the universe contained in a boundary, but the very fabric of time and space ends there. If time does not exist beyond it, does God end there too? Or, in “eternal present” terms, is it impossible for him to be ET-simultaneous with anything we find beyond the boundary? If your answer is “no”, if God is omnipresent in such a way that his presence cannot end simply because the universe ends, that pretty much forces you out of both eternal presence and open theistic views of eternity into Aquinas’ camp.
Secondly, it is bounded in time. It almost certainly has a beginning in the “big bang“. It potentially has an end in a “big crunch“, although it looks like we won’t be getting one: we are living in a universe of indefinite, accelerating expansion. Once again it is important to appreciate that the big bang does not just encompass the “stuff” of the universe, but the origin of time and space itself. Does that mean that God had a definite beginning? If your answer is “no”, if God is eternal in such a way that his awareness predates the birth of time itself, that again pretty much forces you back into Aquinas’ view of eternity.
It gets worse. Consider inflationary multiverse theories… actually, don’t. We’ve seen enough.
A time-bound God is not only surprisingly incarnate in his creation, showing particularity in reference frames, movement, and sensitivity to gravity; he also displays a worrying lack of omnipresence, even admitting the potential for a human being to escape him in a black hole. He is clearly not the God of psalmist:
Where shall I go from your Spirit?
Or where shall I flee from your presence?
If I ascend to heaven, you are there!
If I make my bed in Sheol, you are there!
If I take the wings of the morning
and dwell in the uttermost parts of the sea,
even there your hand shall lead me,
and your right hand shall hold me.
If I say, “Surely the darkness shall cover me,
and the light about me be night,”
even the darkness is not dark to you;
the night is bright as the day,
for darkness is as light with you.
If this psalm is right, and Einstein is right, then Aquinas must also be right. Eternity is not an infinite duration in time, but transcends time altogether. Even the utter darkness of a black hole is as light to the eternal God.