I think I would agree partially with both of you. If I assume that there is no information at all .5 is a good choice. Once a bead of any color is pulled out, I can start making guesses on a potential number of beads in the jar from the relative volumes of the jar and the bead, so if I know that there is a finite number of potential colors, I might take a guess as to what the probability of any particular color distribution is. Once a red bead is pulled, I might adjust probability that Omega is not screwing with me etc.
I think I would agree partially with both of you. If I assume that there is no information at all .5 is a good choice. Once a bead of any color is pulled out, I can start making guesses on a potential number of beads in the jar from the relative volumes of the jar and the bead, so if I know that there is a finite number of potential colors, I might take a guess as to what the probability of any particular color distribution is. Once a red bead is pulled, I might adjust probability that Omega is not screwing with me etc.