In 2003, James Alcock Professor of Psychology at York University published "Give the Null Hypothesis a Chance: Reasons to Remain Doubtful about the Existence of Psi", where he claimed that parapsychologists never seem to take seriously the possibility that psi does not exist. Because of that, they interpret null results as indicating only that they were unable to observe psi in a particular experiment, rather than taking it as support for the possibility that there is no psi. The failure to take the null hypothesis as a serious alternative to their psi hypotheses leads them to rely upon a number of arbitrary "effects" to excuse failures to find predicted effects, excuse the lack of consistency in outcomes, and to excuse failures to replicate.