Necessity

Necessity, in a general way denotes a strict connection between different beings,

or the different elements of a being, or between a being and its existence. It is

therefore a primary and fundamental notion, and it is important to determine its

various meanings and applications in philosophy and theology.

In Logic, the Schoolmen, studying the mutual relations of concepts which form

the matter of our judgments, divided the judgments or propositions into

judgments in necessary matter (in materia necessaria), and judgments in

contingent matter (in materia contingenti). (Cf. S. Thom., I Perihermen, lect. xiii.)

The judgments in necessary matter were known as propositiones per se; they

are called by modern philosophers "analytic", "rational", "pure", or "a priori"

judgments. The propositio per se is defined by the Schoolmen as one the

predicate of which is either a constitutive element or a natural property of the

subject. Such is the case with primary truths, metaphysical, and mathematical

principles. (Cf. S. Thom., "in I Anal.", lect. x and xxxv; "de Anima", II, lect. xiv.) It

is by ignoring the last part of this definition and arbitrarily restricting the concept

of analytic judgments to those of which the predicate is a constitutive element of

the subject, that Kant invented the false notion of synthetic-a priori judgments.

Considered under its metaphysical aspect, being in its relation to existence is

dividend into necessary and contingent. A necessary being is one of which the

existence is included in and identical with its very essence. The different beings

which we observe in our daily experience are subject to beginning, to change, to

perfection, and to destruction; existence is not essential to them and they have

not in themselves the reason of their existence; they are contingent. Their

existence comes to them from an external efficient cause. It is from the real

existence of contingent beings that we arrive at the notion and prove the

existence of a necessary being-one that produces them but is not produced, one

whose existence is its own essence and nature, that is at the same time eternal,

all-perfect, infinite, viz., God (see CONTINGENCY). And so in relation to

existence, God alone is absolutely necessary, all others are contingent.

When we consider the divers beings, not from the point of view of existence, but

in relation to their constitution and activity, necessity may be classified as

metaphysical, physical, and moral.

Metaphysical necessity implies that a thing is what it is, viz., it has the

elements essential to its specific nature. It is a metaphysical necessity

for God to be infinite, man rational, an animal a living being. Metaphysical

necessity is absolute.

Physical necessity exists in connection with the activity of the material

beings which constitute the universe. While they are contingent as to their

existence, contingent also as to their actual relations (for God could have

created another order than the present one), they are, however,

necessarily determined in their activity, both as to its exercises and its

specific character. But this determination is dependent upon certain

conditions, the presence of which is required, the absence of one or the

other of them preventing altogether the exercise or normal exercise of this

activity. The laws of nature should always be understood with that

limitation: all conditions being realized. The laws of nature, therefore,

being subject to physical necessity are neither absolutely necessary, as

materialistic Mechanism asserts, nor merely contingent, as the partisans

of the philosophy of contingency declare; but they are conditionally or

hypothetically necessary. This hypothetical necessity is also called by

some consequent necessity.

Moral necessity is necessity as applied to the activity of free beings. We

know that men under certain circumstances, although they are free, will

act in such and such a way. It is morally necessary that such a man in

such circumstances act honestly; it is morally necessary that several

historians, relating certain facts, should tell the truth concerning them.

This moral necessity is the basis of moral certitude in historical and moral

sciences. The term is also used with reference to freedom of the will to

denote any undue physical or moral influence that might prevent the will

from freely choosing to act or not act, to choose one thing in preference to

another. The derivatives, necessitation and necessarianism, in their

philosophical signification express the doctrine that the will in all its

activity is invariably determined by physical or psychical antecedent

conditions (see DETERMINISM; FREE WILL).

In theology the notion of necessity is sometimes applied with special meaning.

Theologians divide necessity into absolute and moral. A thing is said to be

absolutely necessary when without it a certain end cannot possibly be reached.

Thus revelation is absolutely necessary for man to know the mysteries of faith,

and grace to perform any supernatural act. Something is said to be morally

necessary when a certain end could, absolutely speaking, be reached without it,

but cannot actually and properly be reached without it, under existing conditions.

Thus, we may say that, absolutely speaking, man as such is able to know all the

truths of the natural order or to observe all the precepts of the natural law; but

considering the concrete circumstances of human life in the present order, men

as a whole cannot actually do so without revelation or grace. Revelation and

grace are morally necessary to man to know sufficiently all the truths of the

natural law (cf. Summa Theologica, I:1:1; "Contra Gentil.", I, iv).

Again, in relation to the means necessary to salvation theologians divide

necessity into necessity of means and necessity of precept. In the first case the

means is so necessary to salvation that without it (absolute necessity) or its

substitute (relative necessity), even if the omission is guiltless, the end cannot

be reached. Thus faith and baptism of water are necessary by a necessity of

means, the former absolutely, the latter relatively, for salvation. In the second

case, necessity is based on a positive precept, commanding something the

omission of which, unless culpable, does not absolutely prevent the reaching of

the end.

MERCIER, Ontologie (Louvain, 1902), ii, 3; RICKABY, First Principles of Knowledge (London,

1902), I, v; IDEM, General Metaphysics (London, 1901), I, iv.

George M. Sauvage

Transcribed by Michael T. Barrett

Dedicated to Carmen Schmitz

The Catholic Encyclopedia, Volume X

Nihil Obstat, October 1, 1911. Remy Lafort, S.T.D., Censor

Imprimatur. +John Cardinal Farley, Archbishop of New York

The Catholic Encyclopedia: NewAdvent.org