Is Bilocation/Multilocation Possible?
Many saints in the history of the Catholic Church have performed a miracle which is referred to as bilocation or multilocation, the ability to appear in two places at once. The question arises, however: is such a thing possible? Even with God’s omnipotence, would multilocation constitute an impossibility? Aristotelian philosophy, and its extrapolation by St. Thomas Aquinas, help us understand this miracle more clearly.
Aristotle distinguishes “place” as proper place and common place. Proper place is determined by the dimensions of a contained thing within a container, contrasted with common place which is the interior dimensions of the container itself, with the “container” indicating the thing which by its containment provides place to a thing. Accordingly, multilocation is only possible if something is in place improperly, i.e. “when its dimensions are not measured by the dimensions of the place.” In this way, something can be properly in one place and improperly in another; since for something to be a body it must be in a place properly, this improper multilocation could only be done in an immaterial or purely formal way, which ways are listed as “informatively,” “operatively” and “sacramentally”. Matter, as the principle of individuation of species through quantity (the extension of parts through space and time), cannot possibly multilocate properly speaking (with change of place requiring motion, otherwise wholly new matter would need to be created in the alternate place), but form can do so because it has no extrinsic dimensions. For this reason, it is possible for a saint to multilocate, if he does so in a purely formal or substantial sense, i.e. spiritually rather than materially, since as a material being he could not be wholly in two places at once; for forms which cannot subsist apart from matter, like those of plants and irrational animals, even multilocation by improper place is impossible.
However, for those who are already resurrected, like the Blessed Virgin and Our Lord, whose bodies are spiritual bodies while still remaining authentically human bodies, (1 Cor 15:44) it would seem plausible for them to appear in multiple places at once even in a bodily way, since their whole substance is spiritual in nature. This is evidenced most clearly by the Blessed Sacrament which, as the spiritual Body of Christ, has no dimensions properly limiting it in place and so multilocates “after the manner of a substance”. Possessing their own internal quantity but lacking any external dimensional limitations, resurrected spiritual bodies like these, and like those all humans will possess in the final resurrection, are “in place” only by their own will, limiting themselves to the dimensions of a specific place at a certain time when, in truth, this limitation is unnecessary for them. They are not omnipresent, nor are purely spiritual beings like angels, but they cannot be contained unless they choose to be so, like Christ desiring to be accidentally contained under the suspended dimensions of bread and wine, or like Our Lady appearing at Lourdes, Guadalupe, etc. Although the Blessed Virgin does not, properly speaking, multilocate in her apparitions (normally), she is not limited by the place she chooses or is sent to appear in, and being resurrected, she would be able to multilocate, like her Son, through improper place. For this reason, she can even appear in a place which is not the natural place of a material human body, just as the resurrected Christ could walk through the locked door of the Cenacle. (Jn 20:19)
 Henri Grenier, Philosophy of Nature, vol. 11 of _Thomistic Philosophy_, 2nd ed. (Charlottetown, Canada: St. Dunstan’s University, 1950), 92.
 Grenier, Philosophy of Nature, 93.
 Grenier, Philosophy of Nature, 93.
 Larry Peterson, “Did you know the 1st apparition of the Blessed Mother was an act of bilocation?” at Aleteia (12 October 2017), at www.aleteia.org.