the theory that the moon was formed by a collision between the earth and a Mars-sized planetesimal.
The reason we would accept this theory as true is because it has survived criticism as an explanation while its rivals have not. If another rival theory is still in contention by also having survived criticism then there is a problem and this problem is not going to be resolved by computing, somehow, probabilities that the theories are true. To solve the problem you are going to have to come up with better criticisms or, possibly, alternative theories.
One difference between theories and events is that the counterfactuals of an event exist (in the multiverse). So it makes sense to talk about the probability of an event: the counterfactual events are real and occur to a greater or lesser measure in the multiverse. A false theory, by contrast, is simply false, it has no connection to reality. How do you assign anything other than an arbitrary probability to something that simply cannot be? Fortunately we don’t have to: we have Popperian epistemology.
A false theory, by contrast, is simply false, it has no connection to reality.
How do you assign anything other than an arbitrary probability to something
that simply cannot be?
Intrade knows that one! At the Higgs boson bet over 200 people think they know how to assign a probability to the issue.
1: By using the counterfactuals in the Tegmark Level IV multiverse.
2: By giving it a probability of 0. If T is falsified, that means P(D|T)=0 - we obtained data that T claims is impossible. In this case, Bayes’ theorem sets P(T|D)=0. Bayesianism includes all correct thinking tools, including Popperian epistemology.
But is P(D|T) really 0? We could have made a mistake and not recorded the correct data. Certainly scientists in the past have done so, and thought that they falsified theories that they didn’t falsify. In this case, P(D|T) is very small but nonzero, and so is P(T|D) (unless p(D|~T) is also very small.)
3: You cannot avoid giving a probability. Because of Cox’s theorem, which says we must use probability theory to reason about uncertainty (although I must confess that the assumption that we must use a single real number to reason is rather strong.)
Counterfactuals of the sort of theory that Perplexed describe do exist in a Quantum Multiverse; why not assign them probabilities?
Anyway, why would you want to make your entire epistemology contingent on a particular theory of physics? It sounds like the CR would collapse if Copenhagen turned out to be correct.
Yes, counterfactuals do exist in some of Perplexed examples. There are alternative universes where Earth does not have a moon, or it does have a moon but it was not formed by a collision with a planetesimal. However, in this universe, the one we are observing now, the moon either was or it was not formed in such a way. There is no middle ground. Finding evidence consistent with the theory does not make the theory truer or more likely—what the evidence does is supply us with criticisms of rival theories.
CR is not independent from physics, nor can it be. The laws of physics entail the existence of universal computers and of universal knowledge creators. As David Deutsch has shown, there are deep connections between multiversal quantum physics and the theory of information. If Cophenhagen should turn out to be true it would impact on many things and not the least of which would be CR.
The reason we would accept this theory as true is because it has survived criticism as an explanation while its rivals have not. If another rival theory is still in contention by also having survived criticism then there is a problem and this problem is not going to be resolved by computing, somehow, probabilities that the theories are true. To solve the problem you are going to have to come up with better criticisms or, possibly, alternative theories.
One difference between theories and events is that the counterfactuals of an event exist (in the multiverse). So it makes sense to talk about the probability of an event: the counterfactual events are real and occur to a greater or lesser measure in the multiverse. A false theory, by contrast, is simply false, it has no connection to reality. How do you assign anything other than an arbitrary probability to something that simply cannot be? Fortunately we don’t have to: we have Popperian epistemology.
Intrade knows that one! At the Higgs boson bet over 200 people think they know how to assign a probability to the issue.
http://www.intrade.com/jsp/intrade/common/c_cd.jsp?conDetailID=622297&z=1224442713385
The bet is for an event:
Shrug.
1: By using the counterfactuals in the Tegmark Level IV multiverse.
2: By giving it a probability of 0. If T is falsified, that means P(D|T)=0 - we obtained data that T claims is impossible. In this case, Bayes’ theorem sets P(T|D)=0. Bayesianism includes all correct thinking tools, including Popperian epistemology.
But is P(D|T) really 0? We could have made a mistake and not recorded the correct data. Certainly scientists in the past have done so, and thought that they falsified theories that they didn’t falsify. In this case, P(D|T) is very small but nonzero, and so is P(T|D) (unless p(D|~T) is also very small.)
3: You cannot avoid giving a probability. Because of Cox’s theorem, which says we must use probability theory to reason about uncertainty (although I must confess that the assumption that we must use a single real number to reason is rather strong.)
Counterfactuals of the sort of theory that Perplexed describe do exist in a Quantum Multiverse; why not assign them probabilities?
Anyway, why would you want to make your entire epistemology contingent on a particular theory of physics? It sounds like the CR would collapse if Copenhagen turned out to be correct.
Yes, counterfactuals do exist in some of Perplexed examples. There are alternative universes where Earth does not have a moon, or it does have a moon but it was not formed by a collision with a planetesimal. However, in this universe, the one we are observing now, the moon either was or it was not formed in such a way. There is no middle ground. Finding evidence consistent with the theory does not make the theory truer or more likely—what the evidence does is supply us with criticisms of rival theories.
CR is not independent from physics, nor can it be. The laws of physics entail the existence of universal computers and of universal knowledge creators. As David Deutsch has shown, there are deep connections between multiversal quantum physics and the theory of information. If Cophenhagen should turn out to be true it would impact on many things and not the least of which would be CR.