Big Ho, the null hypothesis, regarding Santa Claus? A null hypothesis specifies the null position, one of no effect, perhaps a generally accepted default position, the status quo, or an established explanation. It should be a statement that can be falsified. But if this null hypothesis is true and Santa Claus does not exist, how can evidence possibly be gathered to refute this? This would be an incredibly difficult task. To reject this null hypothesis we would need evidence that Santa Claus does exist. Perhaps such as this cartoon by Dave Coverly.
Miracle on 34th Street with thousands of letters addressed and delivered to Santa.
contradicted by the laws of physics (see also here).
But with this null hypothesis and its easier approach to falsifiability, if we don't collect the evidence, we accept the default state:
Santa Claus does exist.