Monday, September 12, 2016

A defense of the five minute hypothesis (given a certain false assumption)

Plausibly:

  1. If the universe came into existence either for no cause at all or randomly, it is a priori more likely that it came into existence in a higher-entropy state rather than a lower-entropy one.
  2. If the universe came into existence fully-formed five minutes ago ("five minute hypothesis"), it came into existence in a higher-entropy state than if it came into existence 13.8 billion years ago ("scientific orthodoxy").
  3. So, if the universe came into existence either for no cause at all or randomly, the five minute hypothesis would be a priori more likely than scientific orthodoxy.
  4. But there is no a posteriori evidence for scientific orthodoxy over the five minute hypothesis.
  5. So, if we think the universe came into existence either for no cause at all or randomly, it is not rationally consistent for us to believe scientific orthodoxy over the five minute hypothesis.
I personally think premise (1) is dubious: I doubt there are meaningful probabilities for the universe to come into existence for no cause at all or randomly. But if there are no meaningful probabilities, then it is not a priori more likely that it come into existence as scientific orthodoxy claims, and the rest of the argument should continue to go through.

Of course, I think we should believe scientific orthodoxy over the five minute hypothesis, so we should reject the no-cause and randomness hypotheses in (1).

An amusing rhetorical way to present the argument is that if the universe came into existence for no cause at all or randomly, we shouldn't prefer scientific orthodoxy to certain young earth views.

6 comments:

Michael Gonzalez said...

This is a really cool argument. I don't think people realize just how pernicious an abandonment of the causal presumption would be to their entire scientific worldview (unless they opt for an open embracing of the Taxi-Cab Fallacy, I suppose).

IanS said...

The five minute hypothesis, like brain-in-a-vat, would be consistent with almost any present evidence. So we cannot reject it on the basis of evidence (premise 4). But for just this reason, it is completely useless; if true, it would tell us almost nothing about the present that we don’t already know. We don’t so much reject it as ignore it. Scientific orthodoxy, by contrast, makes strong statements about the present state of the universe. And these statements mostly seem to be true. So we run with it (without necessarily believing it) for as long as it seems to work. Then we change it...

Rational Theist Matt said...
This comment has been removed by the author.
Rational Theist Matt said...

Hi Dr. Pruss

I have been formulating 5 arguments in support of a causal over an acausal universe in turn for supporting P1 of a Kalam Cosmological Argument. Your argument here is intriguing and would add a 6th argument in support of a causal universe.

However I'm not sure how in P1

If the universe came into existence either for no cause at all or randomly, it is a priori more likely that it came into existence in a higher-entropy state rather than a lower-entropy one.

you derive that, 'it is a priori more likely that it came into existnce in a higher-entropy state rather than a lower-entropy state'

Could you elaborate when you have the time?

Thanks
Matt

Alexander R Pruss said...

A standard explanation of why entropy is increasing is that, roughly, there are a lot more high-entropy states than low-entropy ones, so it is much more likely that one will transition from low to high entropy rather than the other way around.

Rational Theist Matt said...

Thanks, I appreciate you taking to the time to provide feedback.