So, my options are guessing that the rigged die will land on 1, or <2,3,4,5,6>.
I do not know which number it is rigged to land on.
Therefore I cannot make any assumptions about which number it is rigged to land on.
In reality, the probability of the number it lands on is:
rigged number=1
other numbers=0.
But to me, the probability of each number being the rigged number is 1/6. So adding that fact into my calculation does nothing to influence my decision. All I know is, guessing that it will land on a number higher than 1 contains 5 out of the 6 possible outcomes, while guessing 1 contains 1 out of 6 possible outcomes. Therefore it is more reasonable.
How is this any different from simple probability?
Probability does not hinge on truth; that is, the fact that it may be rigged to land on 1 in no way undercuts the rationale that given what I know, is it more probable to guess not-1 than 1.
It is only because it is more probable to guess not 1 that makes it "more reasonable". The fact that the dice is rigged is negated by the fact that I do not know which number it is rigged to land on. Thus each number has 1/5 chance of being the rigged number. So there is no point introducing either element. You could have simply asked me to guess 1 or not-1 with a fair die. The analysis is exactly the same.