Necessity
NECESSITY
Whatever is done by a cause or power that is irresistible, in which sense it is opposed to freedom. Man is a necessary agent, if all his actions be so determined by the causes preceding each action, that not one past action could possibly not have come to pass, or have been otherwise than it hath been, nor one future action can possibly not come to pass, or be otherwise than it shall be. On the other hand, it is asserted, that he is a free agent, if he be able at any time, under the causes and circumstances he then is, to do different things; or, in other words, if he be not unavoidably determined in every point of time by the circumstances he is in, and the causes he is under, to do any one thing he does, and not possibly to do any other thing. Whether man is a necessary or a free agent, is a question which has been debated by writers of the first eminence, Hobbes, Collins, Hume, Leibuitz, Kaims, Hartley, Priestley, Edwards, Crombie, Toplady, and Belsham, have written on the side of necessity; while Clarke, King, Law, Reid, Butler, Price, Bryant, Wollaston, Horsley, Beattie, Gregory, and Butterworth, have written against it.
To state all their arguments in this place, would take up too much room; suffice it to say, that the Anti- necessarians suppose that the doctrine of necessity charges God as the author of sin; that it takes away the freedom of the will, renders man unaccountable, makes sin to be no evil, or morality or virtue to be no good; precludes the use of means, and is of the most gloomy tendency. The Necessarians deny these to be legitimate consequences, and observe that the Deity acts no more immorally in decreeing vicious actions, than in permitting all those irregularities which he could so easily have prevented. The difficulty is the same on each hypothesis. All necessity, say they, doth not take away freedom. The actions of a man may be at one and the same time free and necessary too. It was infallibly certain that Judas would betray Christ, yet he did it voluntarily. Jesus Christ necessarily became man, and died, yet he acted freely. A good man doth naturally and necessarily love his children, yet voluntarily. It is part of the happiness of the blessed to love God unchangeably, yet freely, for it would not be their happiness if done by compulsion.
Nor does it, says the Necessarian, render man unaccountable, since the Divine Being does no injuries to his rational faculties; and man, as his creature, is answerable to him; besides he has a right to do what he will with his own. That necessity doth not render actions less morally good, is evident; for if necessary virtue be neither moral nor praise-worthy, it will follow that God himself is not a moral being, because he is a necessary one; and the obedience of Christ cannot be good because it was necessary. Farther, say they, necessity does not preclude the use of means; for means are no less appointed than the end. It was ordained that Christ should be delivered up to death; but he could not have been betrayed without a betrayer, nor crucified without crucifiers. That it is not a gloomy doctrine, they allege, because nothing can be more consolatory than to believe that all things are under the direction of an all-wise Being; that his kingdom ruleth over all, and that he doth all things well. So far from its being inimical to happiness, they suppose there can be no solid true happiness without the belief of it; that happiness without the belief of it; that it inspires gratitude, excites confidence, teaches resignation, produces humility, and draws the soul to God. It is also observed, that to deny necessity is to deny the foreknowledge of God, and to wrest the sceptre from the hand of the Creator, and to place that capricious and undefinable principle.
The self-determining power of man, upon the throne of the universe. Beside, say they, the Scripture places the doctrine beyond all doubt, Job 23:13-14. Job 34:29. Pro 16:4. Is. 45: 7. Act 13:48. Eph 1:11. 1Th 3:3. Mat 10:29-30. Mat 18:7. Luk 24:26. Joh 6:37.
See the works of the above-mentioned writers on the subject; and articles MATERIALISTS, and PRE-DESTINATION.
Fuente: Theological Dictionary
necessity
A word which denotes that which must be as it is without the possibility of being otherwise. It is opposed to contingency, a state or condition or event which need not be as it is, and hence may be, or might have been, otherwise. Logical or mathematical necessity is that which unavoidably, unalterably follows from accepted principles or postulates. Physical necessity is but the constant behavior of the things of nature; thus, the sun must rise. Moral necessity is obligatory conduct for beings possessing free will. Thus, it is morally necessary to keep promises and contracts.
Fuente: New Catholic Dictionary
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.
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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 XCopyright © 1911 by Robert Appleton CompanyOnline Edition Copyright © 2003 by K. KnightNihil Obstat, October 1, 1911. Remy Lafort, S.T.D., CensorImprimatur. +John Cardinal Farley, Archbishop of New York
Fuente: Catholic Encyclopedia
Necessity
NECESSITY.We exclude from this article all problems not directly raised by the Four Gospels.
1. Necessity and the Divine nature.Metaphysicians distinguish between (1) contingent existence, and (2) necessary existence. A thing exists contingently, of which the beginning or end or change can be conceived. A thing exists necessarily, of which neither the beginning, nor the end, nor the change can be conceived. The Universe exists contingently, for we can imagine its annihilation; the laws of Nature also exist contingently, for we can imagine them altered. On the other hand, the laws of Reason, of Mathematics, and of (fundamental) Morality exist necessarily, for we can imagine no beginning or end or change in them.
Thus there never was, or will be, or could be, a time when things which are equal to the same thing could be unequal to one another. Nor can we imagine a time, or a world, in which cruelty would be other than odious, and lying other than contemptible. If cruelty and deceit were seated on the throne of the universe, they would still be what they are, odious and contemptible; and benevolence and truth, their opposites, would still be what they are, admirable and praiseworthy. Time and the vicissitudes of things can make no difference to the laws of Reason and the Moral Law. These are eternally and immutably true,true not only to the human mind, but to every rational mind that does or can exist; valid not only in this universe but in all possible universes.
There exists, therefore, a body of eternal and necessary truth. But this conception of necessary truth carries with it the further conception of necessary Being, or necessary Substance. A truth cannot exist as it were in the air, or in an infinite void: it must be true to some mind. And since the truths in question are independent of all created minds, there must exist some Eternal Uncreated Mind, to which these truths are eternally true. Moreover, since the truths are partly moral truths, this Mind must be moral, or, to use the language of religion, holy. Now it is obvious that to this Infinite Mind the predicate of necessary existence belongs in a higher degree than it belongs to what is called necessary truth. The laws or truths which are called necessary derive their necessary character from the fact that they are the laws of His Mind; but He, the Ultimate and Absolute Mind itself, exists with a degree of necessity transcending theirs. They inhere in Him, not He in them, and consequently He, the Infinite, Absolute, Ultimate Substance, is not only necessarily existent, but also self-existent.
The self-existence, or necessary existence, of the One True, Living, Personal God is a fundamental doctrine of Scripture. It was taught, according to the traditional exegesis of Exo 3:14, to Moses at the bush, and our Lord endorsed this view of the meaning of the Mosaic revelation (Joh 8:58). According to the Johannine theology (with which the Pauline is in essential agreement), necessary existence belongs primarily and originally to the Father, who is emphatically (with the article), and the Living One ( , Joh 6:57). To Jesus also, as consubstantial Son, belongs eternal and necessary existence (Joh 8:58). He has life in himself (Joh 5:26), and is to creatures the resurrection and the life (Joh 11:26). Yet He has this life in himself by derivation from the Father (Joh 5:26, Joh 6:57), and consequently is (in this aspect) an Effect, of which the Father is the Cause.* [Note: Quite Scriptural, therefore, is the Greek theology which regards the Father as , and the Son and Spirit as ]
2. Necessity and the Divine freedom.The Divine freedom, though absolute in the sense that God is free to achieve all that is possible, is limited by the laws of necessary truth and necessary substance as defined in 1. Thus, since the laws of Reason are eternally valid, He cannot not achieve the essentially irrational, or (what is really the same thing) the essentially impossible. For instance, He cannot annihilate the past, or make the angles of a plane triangle unequal to two right angles. Similarly, since He is a necessary Substance, He cannot will His own annihilation; and since He is the supreme necessary, Good (Mar 10:18), He cannot cease to be good, or will what is evil.
The necessary character of the Divine perfections is fully recognized in Scripture [Note: The perfections of the Son of God have the same necessary character as those of the Father (see Heb 13:8).] (Psa 102:24-27, Mal 3:6, Num 23:19, Heb 13:8, Jam 1:17), as also is the doctrine that Gods freedom is limited by His character. All that is worthy of Him, He can perform, but deceit, cruelty, and injustice are to Him impossible (Gen 18:25, Job 8:3 etc.).
3. Necessity and the laws of Nature.It is an important corollary of the Divine freedom, that the laws of Nature do not possess immutable and necessary validity. So far from Nature being a selfcontained system of blind, inexorable, materialistically determined forces, it is a realm of Providence, in which a Being friendly to man guides the course of events providentially, with the object of securing ultimately to each individual his proper good (Mat 10:29 ff.).
In both Testaments the laws and operations of Nature are regarded as expressions of Jehovahs free, will (Genesis 1, Psalms 104, Job 26, Mat 5:45; Mat 6:26 ff. etc.), and consequently as capable of being providentially or miraculously interfered with (Exodus 3-15, etc.). The NT lays particular stress upon Christs control over the forces of Nature (Joh 21:1 ff., Mat 14:22 ff. etc.; see esp. Luk 8:25 Who then is this that commandeth even the winds and water, and they obey him?).
4. Necessity and human affairs.The recognition of God as the sole Absolute and Ultimate Being, excludes the heathen conception of an inscrutable Fate or Necessity () to which gods and men are subject, but it does not of itself exclude the doctrine of Theological Determinism as taught by Calvin. The advocates of this view can appeal plausibly to a considerable number of NT passages.
Thus there are texts which teach that the general course of events is predetermined from eternity (Eph 1:4; Eph 3:11, 2Ti 1:9, Tit 1:2, 1Pe 1:20 etc.), and others which seem to deny human freedom of choice. Most of these are in the Fourth Gospel; see, e.g., Joh 6:37 All that the Father giveth me shall come unto me (cf. Joh 6:39); Joh 6:44 No man can come unto me, except the Father draw him ( ); Joh 10:28 they shall never perish, and no one shall snatch them out of my hand; Joh 12:39 for this cause they could not believe, for that Isaiah saith again, He hath blinded their eyes, and hardened their heart; Joh 17:9 I pray for them, I pray not for the world; Joh 17:12 not one of them perished, but the son of perdition, that the scripture might be fulfilled (cf. Joh 13:18, Joh 17:12, Mat 26:24). Even in the Synoptics we have Mat 13:11 ff. unto you it is given to know the mysteries of the kingdom of heaven, but to them it is not given, etc.; Mat 18:7 it must needs be that offences come ( ); see also Mat 24:6 and Mat 26:24.
But these passages of deterministic tendency are balanced by others of opposite import.
Thus Christs invitation to be saved is addressed not to selected individuals, but to all men: Come unto me, all ye that labour and are heavy laden (Mat 11:28); it is not the will of your Father which is in heaven, that one of these little ones should perish (Mat 18:14); And I, if I be lifted up, will draw all men unto myself (Joh 12:32); cf, 1Ti 2:4 God will have all men to be saved, and to come unto the knowledge of the truth.
Since, however, some reject Gods benevolent purpose, and refuse to be saved (Mat 25:41; Mat 26:24, Joh 17:12), it follows that the human will is free, and that the apparently deterministic passages of Scripture must be so interpreted as to leave room for human freedom. We are led, therefore, to some such view as this, that only the main events of human history are absolutely determined beforehand. The persons by whom, and the times when, the Divine purposes are to be realized, are not predetermined absolutely, but only conditionally. Thus God willed conditionally that the Chosen People should play the leading part in winning the world to the gospel of Christ (Isaiah 60-62, etc.), but, when they proved unfaithful, the Gentiles were called (Mat 21:43; Mat 8:11-12 etc.). Similarly the time of the Last Judgment is not fixed absolutely, but only conditionally (Mar 13:32 compared with 2Pe 3:12 (Revised Version margin) ). Applying the same principle to the interpretation of the apparently deterministic passages quoted above, we conclude that Eph 1:4; Eph 3:11 etc. refer mainly to conditional predetermination; that all that the Father giveth me (Joh 6:37) are simply those whom the Father foresaw would be genuine believers; that the statement that no one (i.e. no hostile power) shall snatch them out of my hand (Joh 10:28) does not preclude the possibility that they may snatch themselves out of Christs hand by unfaithfulness; that the drawing of the Father (Joh 6:44) is the attraction of Divine Love, not the Irresistible Call of Calvinism; that the I pray not for the world of Joh 17:9 is to be read in the light of Joh 17:23, that the blinding and hardening of Joh 12:40 are a penalty for past sin; and that even the case of Judas was not one of individual predestination. The general principle bearing upon the case of Judas is laid down in Mat 18:7 Woe unto the world because of occasions of stumbling! for it must needs be that the occasions come; but woe to that man through whom the occasion cometh. That is to say, in a wicked world great crimes are morally certain to be committed, but there is no need for any individual to commit them, therefore woe to that individual by whom they are committed. To apply this to the case of Judasthe world being what it was, alienated from God and full of treachery and malice, some one was morally certain to betray Jesus to death. But that some one need not have been Judas. He freely undertook the evil business, and therefore his condemnation is just (Mat 26:24).
5. The predetermination of the events of Christs life.Much stress is laid by the Fourth Evangelist on the predetermination of the events of Christs life, even with regard to such details as their precise dates and incidental circumstances.
See, e.g., Joh 2:4 Mine hour (for changing the water into wine) is not yet come [it came a few minutes later]; Joh 7:8; I go not [yet] up unto this feast, because my time is not yet fulfilled [it was fulfilled a few days afterwards]; Joh 7:30 no man laid his hand on him, because his hour was not yet come (cf. Joh 8:20); Joh 12:23 the hour is come that the Son of Man should be glorified [by death]; Joh 12:27 for this cause came I unto this hour [of my death]; Joh 13:1 knowing that his hour was come that he should depart out of this world unto the Father; Joh 17:1 Father, glorify thy Son [by death and resurrection], that thy Son may glorify thee. Cf. Mat 26:39; Mat 26:53, Luk 13:33, which imply that the length of Christs ministry and the time of His death were predetermined; also the very strong expression in Luk 22:22 the Son of man indeed goeth as it hath been determined ( ). In all these passages the language is strongly predestinarian, but, for the reasons given in the preceding section, the present writer holds that conditional predestination is, for the most part, meant.
6. The necessary fulfilment of prophecy.According to the ordinary view, it is the nature of the future event that determines the nature of the prophecy. But often in the Gospels it is the nature of the prophecy that is regarded as determining the nature of the future event. This conception is specially characteristic of the First and Fourth Gospels, but it is not peculiar to them.
In St. Matthew, Christ is born of a virgin at Bethlehem, is named Jesus, sojourns in Egypt, resides at Nazareth, migrates to Capernaum, heals the sick, speaks in parables, enters Jerusalem riding an ass, is deserted by the disciples, is betrayed and put to death, that it might be fulfilled which was spoken by the Lord through the prophet ( , …: so, with slight variations of phrase, Mat 1:22; Mat 2:15; Mat 2:23; Mat 8:17; Mat 12:17; Mat 13:35; Mat 21:4; Mat 26:53; cf. Mat 2:5; Mat 13:14-15; Mat 26:31; Mat 27:9). similarly, St. John regards the blindness of Israel as the result of a prophecy of Isaiah (Joh 12:39, referring to Joh 6:9); the betrayal of Jesus as happening that the scripture (i.e. Psa 41:9) might be fulfilled ( ); the prevalent hatred of Jesus as coming to pass that the word may be fulfilled that is written in their law [viz. in Psa 35:19; Psa 69:4], They hated me without a cause. See also Joh 17:12, where the son of perdition perishes that the scripture might be fulfilled; Joh 19:24, where the casting of lots is necessitated by the prophecy, They parted my garments among them (Psa 22:18); Joh 19:36, where the piercing of Christs side takes place to fulfil Psa 34:20, and the refraining from breaking His legs to fulfil Exo 12:46; cf. also Exo 18:9 and Exo 20:9. For Synoptic parallels see Luk 24:26; Luk 24:44.
Without entering deeply into the philosophy of the question, we may point out that the two views in question do not necessarily exclude one another. We may suppose that God has a plurality of motives for causing or allowing events to happen, and that when events have been predicted by a duly accredited prophet, one of His motives in causing or allowing them to happen, is to maintain the credit of the prophet. This, at any rate, seems to be the view of the Evangelists, who esteem prophecy so highly that they regard a prediction once uttered by a prophet as (in a sense) placing God under a moral obligation to fulfil it. Jesus Himself, on several occasions, acknowledged the obligation of fulfilling the ancient prophecies (see Mat 26:53; Mat 16:21; Mat 21:4, Joh 19:28, etc.).
7. The necessity of means to ends.The musts of Christ, of which there are numerous examples in the Gospels, generally refer to the necessity He was under (in order to fulfil the purpose of His Incarnation) to do or to suffer certain things. His original purpose to become incarnate, and to redeem the world, was freely chosen (Php 2:7, 2Co 8:9 etc.); but the choice once made, a whole series of experiences (many of them painful and humiliating) became necessary.
As a child of twelve, He was already conscious, according to one interpretation of Luk 2:49 (see (Revised Version margin) ), of the necessity of being about His Fathers business, and the same idea frequently recurs during the ministry. Almost at the beginning of it He declares to Nicodemus that His purpose to give eternal life to believers can be achieved only by His death: As Moses lifted up the serpent in the wilderness, even so must () the Son of Man be lifted up (Joh 3:14).* [Note: Some critics assign this saying to the Evangelist, not to Jesus.] He frequently declared the necessity He was under of working during the appointed timeWe must () work the works of him that sent me, while it is day: the night cometh, when no man can work (Joh 9:4); Howbeit I must () go on my way to-day, and to-morrow, and the day following, for it cannot be ( ) that a prophet perish out of Jerusalem (Luk 13:33); My meat is to do the will of him that sent me, and to accomplish his work (Joh 4:34; cf. Joh 5:17; cf. Joh 5:19 etc.). His visit to Zacchaeus was determined by a redemptive purpose (Luk 19:5 to-day I must () abide at thy house. From the time of Peters confession at (Caesrea Philippi, intimations of the necessity of the Passion and Resurrection become more frequent; From that time began Jesus to show unto his disciples how that he must () go unto Jerusalem, and suffer many things of the elders and chief priests and scribes, and be killed, and the third day be raised up (Mat 16:21); but first must () he suffer many things, and be rejected of this generation (Luk 17:25); Behoved it not ( ) the Christ to suffer these things, and to enter into his glory? (Luk 24:26).
Corresponding to Christs obligation of doing and suffering all that is necessary for mans salvation, is mans obligation of appropriating (if he would be saved) the necessary means. Frequent stress is laid upon the latter obligation in the Gospels: see, e.g., Mat 4:17 (the necessity of repentance), Mat 18:3 (of conversion), Mat 22:37 (of love), Joh 3:5 (of baptism), Joh 6:53 (of the Holy Supper), Joh 15:4 (of abiding in Christ), etc.
Literature.See under Free Will, and add W. James, Necessary Truths in Principles of Psychology, ii. 617 ff.; Boutroux, La contingence des lois de la nature.; J. Edwards, Freedom of the Will; Momerie, Personality; Martineau, Study of Religion, bk. iii. ch. 2; Lotze, Microcosmus, i. 144 ff.; Sturt, Personal Idealism (iii.); A. Moore, Essays (vii.); J. S. Mill, Hamiltons Philosophy Examined (xxvi.), and Logie, bk. vi. ch. 2.
C. Harris.
Fuente: A Dictionary Of Christ And The Gospels
Necessity
A state of affairs is said to be necessary if it cannot be otherwise than it is. Inasmuch as the grounds of an assertion of this kind may in general be one of three very distinct kinds, it is customary and valuable to distinguish the three types of necessity affirmed as
logical or mathematical necessity,
physical necessity, and
moral necessity.
The distinction between these three was first worked out with precision by Leibniz in his Theodicee.
Logical, physical, and moral necessity are founded in logical, physical, and moral laws respectively. Anything is logically necessary the denial of which would violate a law of logic. Thus in ordinary commutative algebra the implication from the postulates to ab-ba is logically necessary, since its denial would violate a logical law (viz. the commutative rule) of this system.
Similarly, physically necessary things are those whose denial would violate a physical or natural law. The orbits of the planets are said to be physically necessary. Circular orbits for the planets are logically possible, but not physically possible, so long as certain physical laws of motion remain true. Physical necessity is also referred to as “causal” necessity.
As moral laws differ widely from logical and physical laws, the type of necessity which they generate is considerably different from the two types previous defined. Moral necessity is illustrated in the necessity of an obligation. Fulfillment of the obligation is morally necessary in the sense that the failure to fulfill it would violate a moral law, where this law is regarded as embodying some recognized value. If it is admitted that values are relative to individuals and societies, then the laws embodying these values will be similarly relative, and likewise the type of thing which these laws will render morally necessary.
While these three types of necessity are generally recognized by philosophers, the weighting of the distinctions is a matter of considerable divergence of view. Those who hold that the distinctions are all radical, sharply distinguish between logical statements, statements of fact, and so-called ethical or value statements. On the other hand, the attempt to establish an a priori ethics may be regarded as an attempt to reduce moral necessity to logical necessity; while the attempt to derive ethical evaluations from the statements of science, e.g. from biology, is an attempt to reduce moral necessity to physical or causal necessity. — F.L.W.