Alan Lightman:

Given some ostensibly miraculous event, almost all scientists will insist on a logical, rational, “natural” explanation. (Scientists dismiss the Miracle of the Sun as the result of local atmospheric effects, spurious images on the retina brought about by staring at the sun, and self-delusion.) If no logical or rational explanation immediately presents itself, most scientists will conclude that a scientific explanation will eventually be forthcoming, rather than abandon their commitment to a totally lawful universe. This prevailing view was articulated to me recently by the Nobel Prize–winning biologist David Baltimore: “If I could not find any way out of believing that a miracle had occurred, would I then believe it to be a miracle? I think the answer is that I would still not believe it to be a miracle, only some outcome that I can’t understand.”

In all my life I have met only one person who claims to have seen a ghost. And the interesting thing about the story is that that person disbelieved in the immortal soul before she saw the ghost and still disbelieves after seeing it. She says that what she saw must have been an illusion or a trick of the nerves. And obviously she may be right. Seeing is not believing.

For this reason, the question whether miracles occur can never be answered simply by experience. Every event which might claim to be a miracle is, in the last resort, something presented to our senses, something seen, heard, touched, smelled, or tasted. And our senses are not infallible. If anything extraordinary seems to have happened, we can always say that we have been the victims of an illusion. If we hold a philosophy which excludes the supernatural, this is what we always shall say. What we learn from experience depends on the kind of philosophy we bring to experience. It is therefore useless to appeal to experience before we have settled, as well as we can, the philosophical question.