WRW has probability 1⁄2 2⁄3 1⁄2 = 1⁄6
WWR has probability 1⁄2 1⁄3 3⁄4 = 1⁄8
This is coherent if you require that the probability of different permutations of the same sequence be the same. An Anti-Laplacian urn must necessarily be finite.
On the other hand, Laplace assigns both a probability of 1⁄12.
WRW has probability 1⁄2 2⁄3 1⁄2 = 1⁄6
WWR has probability 1⁄2 1⁄3 3⁄4 = 1⁄8
This is coherent if you require that the probability of different permutations of the same sequence be the same. An Anti-Laplacian urn must necessarily be finite.
On the other hand, Laplace assigns both a probability of 1⁄12.