I'm trying to get clear on Craig's new a posteriori argument for the beginning of the universe, and I'd be grateful for any constructive feedback. As far as I can make out, the core of his argument can be expressed as follows:
1. The Borde-Guth-Vilenkin Theorem (BGV) is true.
2. If the BGV is true, then each universe or multiverse which has, on average, been expanding throughout its history has a beginning to its expansion. (implication of BGV)
3. Each universe or multiverse has, on average, been expanding throughout its history.
4. Therefore, each universe or multiverse has a beginning to its expansion.
4. Therefore, each universe or multiverse has a beginning to its expansion.
5. Each universe or multiverse that has a beginning to its expansion has a beginning of its existence.
6. If each universe or multiverse has a beginning of its existence, then there is a beginning to the existence of all physical reality -- including all universes and multiverses there may be.
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7. Therefore, there is a beginning to the existence of all physical reality.
Some questions and comments:
(i) I'm assuming (1) is the consensus view among the relevant scientists, and that (2) just falls out of (1).
(ii) I have no idea why we're supposed to accept (3).
(iii) I'm not entirely sure what the justification for (5) is supposed to be, but I think it's roughly as follows: (a) The initial state I of any given expanding universe U must be one of quiescence or activity. But (b) if I was a state of quiescence, then it would've remained in that state forever, as (c) there would be no way for an event to begin within U (which contradicts the assumption that it's expanding). On the other hand, (d) if the initial state of U was one of activity, then the expansion of U would have had an infinite amount of time to start its expansion phase I, in which case (e) it would've been expanding for eternity (which contradicts the assumption that U's expansion had a beginning). Therefore, (f) any universe that has a beginning of its expansion has a beginning of its existence.
As I said, I'm not sure if that's Craig's reasoning, but if it is, it seems pretty bad. One problem with it is that (c) doesn't entail (b). For even if the initial state of a universe were quiescent, and even if there is no way for an event to begin from within a quiescent universe, it doesn't follow that there's no way for a physical entity or event outside of a quiescent universe to initiate activity within it.
Furthermore, the best way I know of to support the inference from (d) to (e) ("if x can be completed in an infinite stretch of time S, then x must (or at least will) be completed within S") is Craig's a priori "immortal counter" argument, but that argument has an undercutting defeater.
Unfortunately, I don't know of another way to support (5), but perhaps there is one, and Craig has stated it somewhere (it may be that it's in his chapter in The Blackwell Companion to Natural Theology, and I missed it, though. It's been a while since I've read it, so it's quite possible that that's what's going on). If so, I'd be grateful for help on this.
(iv) Without independent justification, the inference from the antecedent to the consequent in (6) is an instance of a quantifier shift fallacy or the fallacy of composition. Thus, grant that each universe and multiverse is an inflating structure, and grant that each particular inflating universe or multiverse must have a beginning. It doesn't follow from these claims that the set of all such structures must have a beginning (let alone all physical reality. Note that the argument assumes the two are co-extensive). So, for example, it's epistemically possible that each inflating universe or multiverse has a beginning, but that there is a beginningless series of such universes or multiverses. It's also epistemically possible that there is some non-inflationary structure that's eternal (say, some sort of field structure), from which a finite or infinite number of inflating universes or multiverses arise.
Are such structures scientifically acceptable? Given Craig's ultimate argumentative aims, that's neither here nor there[1]. For Craig's ultimate aim is to establish God as the originating cause of all other concrete entities that exist.[2] As such, it's not enough for Craig to rule out all scientifically acceptable rival hypotheses of the origin of the universe besides theism; he must also rule out all metaphysically acceptable rival hypotheses of the origin of the universe besides theism. Perhaps, though, Craig has other arguments for (5) that can achieve this stricter aim. If so, I'd be grateful to learn what they are.
(v) Assume my reconstruction of Craig's argument adequately captures Craig's reasoning and that all the concerns raised above can be answered. The argument is nonetheless undercut by the following G.E. Moore Shift argument:
1. If all of premises 1-6 are true, then there is a beginning to the existence of all physical reality.
2. There is not a beginning to the existence of all physical reality.
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3. Therefore, not all of premises 1-6 are true.
The argument's valid, and (1) is true in virtue of the validity of my reconstruction of Craig's argument. Furthermore, (2) is justified in virtue of our a priori and a posteriori evidence for the following version of the principle of material causality (PMC): every concrete object (or aggregate thereof) that begins to exist has a material cause of its existence (i.e., it's made from pre-existing stuff, whether material or immaterial). So unless we allow that either (a) physical reality is made out of God's being, (b) physical reality is ultimately made out of some eternal stuff distinct from God, or (c) things that begin to exist but aren't preceded by other events don't need causes (all of which Craig is committed to rejecting), PMC should push one to accept (2).
Now here's the rub: if the G.E. Moore Shift argument is sound, then Craig's argument is unsound. And if Craig's argument is sound, then the G.E. Moore Shift argument is unsound. Unfortunately, The premises in the latter have at least as much going for them as those in Craig's argument. And if that's right, then the epistemic force of each cancels out that of the other, in which case Craig's argument is subject to an undercutting defeater.
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[1] Of course it goes without saying that Craig's posited immaterial, tri-personal creator-out-of-nothing is scientifically unacceptable.
[2] Indeed, Craig also wants to argue that God is the cause of all abstract objects as well, but that's a topic for another day.
15 comments:
How does (d) entail (e)? I believe Morriston adressed something similar in one of his papers. Can't remember which one.
Hi Sebastian,
Ah -- you beat me to the criticism before I finished editing my post. It has now been updated.
Best,
EA
Hi, EA.
You suggested that (c) doesn't entail (b) because "even if there is no way for an event to begin from within a quiescent universe, it doesn't follow that there's no way for a physical entity or event outside of a quiescent universe to initiate activity within it." If universe U1 and universe U2 aren't causally isolated, how might we preserve the initial assumption that there are two distinct universes? Further, if U1 and U2 aren't causally isolated, it seems plausible that this would imply that U1 and U2 aren't spatiotemporally isolated either. If this is right, then it appears that what we're really talking about is the same universe, not an active U1 which causes some effect in a distinct, quiescent U2.
With respect to supporting (4) in your reconstruction, what are your thoughts on what Craig said to Millican in their recent debate? Following Vilenkin, Millican noted that you can evade the BGV theorem by postulating that the universe was contracting prior its expansion. Craig replied by pointing out that, according to Vilenkin, if you postulate a contracting phase prior to the expansion phase, the universe probably won't be capable of reaching the expansion phase by virtue of the "messy singularities." So, probably, since the universe apparently reached the expansion phase, there was no contracting phase, in which case the theorem isn't evaded.
Additionally, what do you make of the notion that if the "universe or multiverse . . . never gets below some non-zero rate of expansion," then not only does the expansion have a beginning, but--more importantly--it follows that the past (of the universe or multiverse) is geodesically incomplete? This seems to partially motivate Vilenkin's recent comment that all our current evidence indicates that the universe had a beginning.
Both http://arxiv.org/abs/gr-qc/0301042 and http://arxiv.org/abs/hep-th/0410270 evade the BVG theorem. They also avoid the 'messy' singularities.
Hi Marc,
Your remarks are extremely helpful. Thanks very much!
Regarding your first point: As an illustration, think of something crudely analogous to the collision of membrane universes in the higher-dimensional bulk of M-Theory. Now imagine an n-dimensional membrane colliding with a quiescent membrane within the bulk. In that scenario, we have activity generated within a quiescent universe from the interaction of a non-quiescent physical object. Now I doubt that this describes physical reality, but it does illustrate an epistemically possible case in support of my point.
Regarding (4): Maybe what you say is right. I wonder, though, if there aren't other ways to avoid non-zero expansion besides contraction. So, for example, why not a non-expanding field of some sort that gives rise to universes? I'm not saying there's evidence for such a thing; I'm just saying that I don't know how to rule it out as highly implausible. I guess my basic worry here is this: suppose Vilenkin is right: if all you've got to work with in your large-scale physical theory that can do the requisite explanatory work is inflating objects, and if they can't explain all that needs explaining, then why not postulate non-inflating entities to do the explanatory work (like a non-expanding field of some sort)? Who knows, though: perhaps non-expanding entities that could do the explanatory work are metaphysically impossible. If so, though, I'd be very interested to know why that's so.
But suppose it is so, and indeed that all of (1)-(4) are true. Is there a way to justify (5)? As I said in the post above, the inference from (5)'s antecedent to its consequent commits either a quantifier shift fallacy or the fallacy of composition. I imagine Craig has interesting things to say on the matter, though.
In the final analysis, though, I feel pushed by a version of the principle of material causality to think the argument is undercut by the G.E. Moore Shift argument stated in the post above.
Best,
EA
Thanks for the links, Sebastian.
"Craig also wants to argue that God is the cause of all abstract objects as well, but that's a topic for another day."
He does? I thought he's spent the last 10 years researching arguments against the existence of abstract objects.
Hi Chad,
No you're right that he'd prefer some form of nominalism or anti-realism about abstract objects, but so far as I've been able to tell, he still wants to leave the back door open on theistic conceptualism. Here I'm thinking of these remarks (which, I believe, are a response to one of your questions to him):
"My first inclination was to adopt some sort of Conceptualism which construes abstract objects as ideas in God’s mind. This may still be the route I’ll take, but the more I’ve studied the problem the more attracted I’ve become to various Nominalistic or anti-realist views of abstract objects which flatly deny their existence rather than re-interpret their existence in terms of conceptual realities." (Emphasis mine. The comment can be found here.)
Of course the reason why he's so keen to adopt one of these views is because he thinks Platonism entails the falsity of Anselmian theism.
I hate being late to this party, but only got time to reply now.
I largely agree with the first criticism in that we have no reason to believe (3). What says our space-time isn't expanding in some larger multiverse that is itself not expanding?
The main objection I'd throw at this is that Craig is just smuggling in his specific brand of presentism (or tensed, or A-Theory of time) when he uses this argument; and that goes against all available scientific evidence. Craig can only justify his alternative views using more complex, unfalsifiable quasi-scientific theories, which he then says he's justified in believing in because he puts either theology or his own metaphysics above empirical scientific evidence. In which case, he can justify believing in just about anything in light of any scientific evidence presented against it.
The last bit I'd say in response to this is that there was some new theories that got some weight behind them with the discovery of the Higgs: http://www.bbc.co.uk/news/science-environment-21499765
Basically, it's almost like having an infinite regress, but without entailing Craig's arguments against the infinite past. The universe has always existed, but goes through different levels of "stability" at some point in each universe, things get unstable (see the link about the Higgs on how/why) and a new universe happens in a big bang. That new universe expands into our current one at the speed of light, obliterating everything as it expands into it. Since "time" is a function of each space-time, each universe has an absolute beginning to its expansion, but we require no "creator".
It's an odd theory and I've not read too much on it, but it at least seems possible.
Thanks for the link about the Higgs boson. I hadn't seen that. Thanks also for raising the point about B-theory. As you point out (and Craig concedes), if the B-theory is correct, then the kalam argument is defeated. I'd add that one need not show that A-theory is false; it's wholly sufficient to show that B-Theory is merely epistemically possible. Craig regularly implies that the former is what's required. Here, as elsewhere, Craig is Craigging.
Ex,
What you say in response to my comment above is correct. (yeah, Craig's answer was to my question, which I can't believe was nearly 6 years ago!). But if this is going to work its way into a formal paper, I think you'd agree with me that it's incorrect or at least misleading to say Craig "wants to argue that God is the cause of all abstract objects as well." He is thoroughgoing nominalist at this point, so he certainly doesn't want argue that God is the cause of abstracta. Conceptualism is for Craig a last resort, and I take it that no one wants to have to resort to arguing for the last resort. ;-)
Hi Chad!
Fair enough :) I suppose I'd revise the claim o say that he's prepared to argue for theistic conceptualism should other non-Platonic accounts fail to pan out.
Best,
EA
Here's what Vic Stenger has to say. To be honest, I don't understand any of the physics, but I'll provide the link:
http://www.colorado.edu/philosophy/vstenger/Cosmo/Origin.pdf
As you probably have seen already (if you watched the Carroll vs WLC debate); the BVG-theorem assumes classic spacetime and gravity; ergo it doesn't show what WLC been saying it shows.
I know this thread is a bit old, but I would like to contribute by pointing out a recent paper published by physicist Andrei Linde, one of the original proponents of the theory of inflation: Inflationary Cosmology after Planck 2013. It can be accessed here: http://arxiv.org/abs/1402.0526
In the last paragraph of page 18 and the first half of page 19, Linde addresses the issue of whether or not eternal inflation is eternal only in the future or also in the past. After referencing the work of Borde, Guth and Vilenkin he concludes that currently there is no reason to expect inflation to be eternal only in the future.
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