A multiverse hypothesis that counters the fine-tuning argument posits laws of nature that vary across physical reality.
A hypothesis that posits laws of nature that vary across physical reality contradicts the uniformity of nature.
A hypothesis that contradicts the uniformity of nature is a global skeptical hypothesis.
Global skeptical hypotheses should be denied.
So, a multiverse hypothesis that counters the fine-tuning argument should be denied.
The thought behind (1) is that the constants in the laws of nature are part and parcel of the laws. This can be denied. But still, the above argument seems to have some plausibility.
Dr Pruss,
ReplyDeleteFor a number of multiverse hypotheses, premise 1 is false. They do not posit multiple or varying cosmic laws in the proper or fundamental sense, but one cosmic meta-law governing a process that as a spin-off produces numerous or an infinite number of causally and/or spatially disconnected universes, each of which may have its own differently "contracted" derivation of that meta-law or "theory of everything" (TOE).
While no expert in the matter, I suspect that the differences between universes would then be due to variations in symmetry breaking and/or the underlying quantum fields' intrinsically indeterministic evolution. They are not due to different TOEs, sensu stricto.
However, there are some multiverses theories which are susceptible to this kind of objection, e.g., theories that claim all conceivable universes or all mathematically conceivable universes must exist. Such theories cause modal collapse and cannot ground safe inductive inferences for reasons I discuss in an upcoming paper in Angelicum (if you'll pardon the shameless plug).
MK
Fair enough. But then those theories posit that our well confirmed generalizations are not actually laws, but merely local generalizations. That's skeptical, too, isn't it?
DeleteAlex
ReplyDeleteI think you should distinguish between a multiverse hypothese that is worked out for the purpose of countering the FTA and multiverse hypotheses that state that, given the laws of nature, mutiple universes are very likely if not inevitable.
The latter, while I am in no position to judge whether they are justified, do no seem to be an example of global skepticism.
Also, if the constants in the laws of nature cannot vary, there is no Fine Tuning Problem.
Sorry for the late response, just saw there was a reply to my comment.
ReplyDeleteAnswer to Dr Pruss' question: No, because this could just be a continuation of a similar process that took us from Newtonian mechanics (laws that are, for all practical purposes, correct in most situations we deal with) to Einstein's relativity. In the latter, Newtonian laws fall out as mathematically derivable approximations that are extrememly accurate in the right context.
You could be right. But there is an interesting disanalogy. In the Newton-to-Einstein move, it turns that the Newtonian claims were never true anywhere--they were just extremely good approximations for objects with moderate speed and energy. In the kind of multiverse scenario I am thinking about, the best laws for accounting for how things are _here_ might be exactly though only locally true. Perhaps that is a distinction that does not make a difference.
ReplyDelete