None of the miracles with which the old histories are filled took place under scientific conditions.

Observation, which has never once been falsified, teaches us that miracles never happen but in times and countries in which they are believed, and before persons disposed to believe them.

No miracle ever occurred in the presence of men capable of testing its miraculous character.

Neither common people nor men of the world are able to do this.

It requires great precautions and long habits of scientific research.