Occam’s Razor (cont.)

Of course we don’t really believe the null hypothesis!
We don’t believe the alternative hypothesis either!
When predictive consequences of H0 and HA are similar:
- H0 is robust to plausible departures from H0
- When HA has many parameters in relation to the amount of data available we may do much worse by using HA
- H0 is robust to (likely) misspecification of parameters qA of HA
But Occam’s razor only works if we’re willing to abandon simple hypotheses when they conflict with observations