### Errata ### 1) The second equation in the right column on p15 has the same expression left and right on the first line. There is no reason for this. 2) The equation in the left column on p21 includes $I_\theta$ in the integral after the bounds had already been specified on the integral. The $I_\theta$ is superfluous and possibly confusing. Throughout the *Measure of an Elf* example, references to Runcorn's prior are inconsistent. The values used in the computations and in the figures were ${\cal M}_{-} = .10, {\cal M}_{0} = .10, {\cal M}_{+} = .80$. 3) In Table 3, the first two values in the rightmost column (Runcorn) should be $.100$ and $.100$ instead of $.050$ and $.150$. 4) At the end of page 16, Runcorn's tokens should be distributed $(10, 10, 80)$. 5) In the Appendix, the provided MATLAB code also had wrong values for Runcorn's model priors. The values used in the example were `[0.10, 0.10, 0.80]`. The m-file on the OSF page has been updated with this correction (https://osf.io/bdtwy/). The print version introduced additional errors. Using the published PDF file's page index: 1) p16, right side: the calculation should give 0.9970, not 0.09970. 3) p20, right side: in the discussion of Example 5, after "their magical counterparts ...", should read $P(\mu > 42)$ instead of $P(\mu > 2)$. The authors thank Dr. David Quarfoot (UC San Diego) for alerting us to these errors.