I. The question whether the same finite being (especially a body) can be at once in two (bilocation) or more (replication, multilocation) totally different places grew out of the Catholic doctrine on the Eucharist. According to this Christ is truly, really, and substantially present in every consecrated Host wheresoever located. In the endeavour to connect this fact of faith with the other conceptions of the Catholic mind theologians make the following distinctions:

The place of a body is the surface of the body or bodies immediately surrounding and in contact with the located body.

A physical body is in place commensurably (circumscriptively) inasmuch as the individual portions of its exterior surfaces answer singly to the corresponding portions of the immediately environing surfaces of the body or bodies that constitute its place.

A being is definitively in place when it is entire in every portion of the space it occupies. This is the mode of location proper to unembodied spirits and to the human soul in the organism whereof it is the "substantial form", i.e. the actuating and vitalizing principle. A spirit cannot, of course, be in loco circumscriptively since, having no integrant parts, it cannot be in extensional contact with the surrounding dimensions. It may be said, therefore, to locate itself by its spiritual activity (will) and rather to occupy than to be occupied by place, and consequently to be virtually rather than formally in loco. Such a mode of location cannot be natural to a physical body. Whether it can be so absolutely, supernaturally, miraculously, by an interference on the part of Omnipotence will be considered below.

A mixed mode of location would be that of a being which is circumscriptively in one place (as is Christ in heaven), and definitively (sacramentally) elsewhere (as is Christ in the consecrated Host).

II. That bilocation (multilocation) is physically impossible, that is, contrary to all the conditions of matter at present known to us, is the practically unanimous teaching of Catholic philosophers in accordance with universal experience and natural science. As to the absolute or metaphysical impossibility, that is, whether bilocation involves an intrinsic contradiction, so that by no exertion even of Omnipotence could the same body be at once in wholly different places - to this question the foregoing distinctions are pertinent.

Catholic philosophers maintain that there is no absolute impossibility in the same body being at once circumscriptively in one place and definitively elsewhere (mixed mode of location). The basis of this opinion is that local extension is not essential to material substance. The latter is and remains what it is wheresoever located. Local extension is consequent on a naturally universal, but still not essentially necessary, property of material substance. It is the immediate resultant of the "quantity" inherent in a body's material composition and consists in a contactual relation of the body with the circumambient surfaces. Being a resultant or quasi effect of quantity it may be suspended in its actualization; at least such suspension involves no absolute impossibility and may therefore be effected by Omnipotent agency. Should, therefore, God choose to deprive a body of its extensional relation to its place and thus, so to speak, delocalize the material substance, the latter would be quasi spiritualized and would thus, besides its natural circumscriptive location, be capable of receiving definitive and consequently multiple location; for in this case the obstacle to bilocation, viz., actual local extension, would have been removed. Replication does not involve multiplication of the body's substance but only the multiplication of its local relations to other bodies. The existence of its substance in one place is contradicted only by non-existence in that same place, but says nothing per se about existence or non-existence elsewhere.

If mixed replication involves no absolute contradiction, definitive replication a fortiori does not.

Regarding the absolute possibility of a body being present circumscriptively in more than one place, St. Thomas, Vasquez, Silv. Maurus, and many others deny such possibility. The instances of bilocation narrated in lives of the saints can be explained, they hold, by phantasmal replications or by aerial materializations. Scotus, Bellarmine, Suarez, DeLugo, Franzelin, and many others defend the possibility of circumscriptive replication. Their arguments as well as the various subtle questions and difficulties pertinent to the whole subject will be found in works cited below.

BALMES, Fundamental Philosophy (New York, 1864); DALGAIRNS, The Holy Communion (London, 1868); FABER, The Bl. Sacrament (Baltimore, 1855); GUTBERLET, Die Metaphysik (Münster, 1880); NYS, Cosmologie (Louvain, 1906); LA FARGE, L'idée de continu (Paris. 1894); PESCH, Philosophia Nat. (Freiburg, 1897); URRABURU, Cosmologia (Valladolid, 1892).

F.P. SIEGFRIED