4. It is written that a star appeared to the wise men who came to worship Jesus; that it went before them to indicate the route to them, and stood still when they had arrived at their destination (Matthew, 2: 1 to 12).
The question is asked, not to ascertain if the statement given by St. Matthew is true, or if it is only a figure of speech to indicate that the wise men were mysteriously guided to the young child, because no means exist whereby it can be examined, but simply to ask if such a thing were possible.
One thing is certain, that the light referred to could not have been a star. They could believe it at that epoch where the stars were thought to be luminous points attached to the firmament, which could fall upon the Earth; but not now, when their nature is known.
The right cause may now be attributed to it: the fact of a light in appearance like a star is possible. A spirit can appear under a luminous form, or transfer a part of his perispiritual fluid to a luminous point. Many facts of this kind, recent and perfectly authentic, have no other cause; and this cause has nothing supernatural about it. (Chap. XIV, from item n° 3 on)