PROBLEM OF NECESSITY AND CONTINGENCY

INTRODUCTION.
The concept of necessity probably orginated from the pre-philosophical concept of fate or fatalism.
FATE AND FATALISM.
The word "fate" comes from the Latin fatum meaning "a prophetic declaration or the utterance of an oracle" (the Greek term meaning the same is moira). That which is fated is that which is destined or decreed to come to pass. Fatalism is the doctrine that all things happen according to an enexorable fate. The term "fate" is pre-philosophical, being derived from mythology. In Greek mythology, fate was the will of Zeus; in Roman mythology, it was the spoken word of Jupiter. In both, fate (the Fata in Latin; the Moirai in Greek) is depicted as three godesses determining the course of human life. One godess spins the thread of life at birth of a human, the second twists the thread life controlling the things that happened during his life, and the third snips it at the death of the human. The concept was important in Greek tragedy where all human concerns are subject to all the gods, and even the gods were subject to this all controlling necessity or fate. The gods could only do what the gods had determined. In Arabic, this concept of fate is expressed by the term kismet and in Islam it is interpreted as the will of Allah. This doctrine of fate is both pre-philosophical and pre-theological. The doctrine came into theological thought as predistination and into philosophy as determinism, of course, being demythologised.
NECESSITY.
The original concept of necessity was expressed by the Greek term anagke. The term "necessity" comes from the Latin ne ("not") and cedere ("to go away") and refers to the concept that all events that happen cannot be other than they are (fate or destiny). Necessity can be affirmed of propositions, of things, and of God. These are referred to as
(1) logical or mathematical necessity,
(2) physical necessity, and
(3) theological necessity.
1. Logical Necessity. When a proposition is said to be necessary is to say that it is not possible to deny the proposition.
  1. Aristotle (384-322 B.C.) distinguishes between necessary and contingent propositions; a necessary proposition is a proposition that cannot be false. The contrary of the necessary is the impossible. The possible is that which may be true or may be false, and whose contrary is not necessarily false. A proposition is contingent if it can be either true or false; the contingent is that which can be otherwise, while that which cannot be otherwise is necessary. The opposite of contingent is another contingent. For example, in the class of colors, the opposite of green is not-green which is another color. The opposite of the necessary is the impossible.
  2. Leibniz (1646-1716) distinguished between absolute necessity, whose denial leads to contradiction, and hypothetical necessity, whose denial does not lead to contradiction (his example was causal necessity). The former are truths of reason, and are analytic.
  3. Kant (1724-1804) found not only necessity in analytic judgments, as he called them, but also in synthetic a prori judgments, which he regarded as both necessary and non-trival. An analytic judgment is one whose predicate merely asserts a characteristic already implicit in the subject; for example, "All bachelors are unmarried." The assertion follows necessarily from the meaning assigned to the term "bachelor". On the other hand, the predicate of the synthetic judgment asserts an idea not implicit in the subject, adding something to the subject; for example, "This book is a paperback." Analytic judgments are a priori in the sense that we know their truth or falsity prior to experience - apart from, or without experience. Synthetic judgments are a posteriori in the sense that we know their truth or falsity only after experience - by means of, and through, experience. The strength of analytic judgments lies in their necessity, and their weakness in that they do not tell us something new. The strength of synthetic judgments lies in their ability to tell us something new, but their weakness is that they have no necessity. If we could have judgments that could provide us with both information and necessity, we would have the best of both kinds of judgments. These would be synthetic a priori judgments, combining the strengths of both synthetic and analytic judgments. Kant did not ask if synthetic a priori judgments are possible, but how are they possible, because he believed that he had found such judgments in the sciences that are both informative and necessary; for example, "7 + 5 = 12", "A straight line is the shortest distance between two points", "In all changes in the physical world the quantity of matter remains unchange", "In all interactions of bodies of matter the action and reaction forces must be equal in magnitude but opposite in direction."
2. Physical Necessity. When necessity is affirmed of things, one is saying that things cannot possibly be otherwise.
  1. Democritus (460-370 B.C.) held that the world-creating motion of the atoms came by necessity from their initially random motion, and this necessity remained in the world once it was structured. That is, there is causal necessity governing the arrangements and changes among the atoms. The present arrangement of atoms is the outcome of antecedent arrangements and the motion of the atoms leading to those arrangements and from those arrangements to the present one.
  2. Stoicism (founded in 108 B.C.) devloped this view further where in the world an ordering universal reason and a physical causality coalesced to produce a system in which everything is controlled by necessity, and nothing could have been otherwise.
  3. Spinoza (1632-1677) perfected this view of the world. He combined logical and causal necessity with each other, so that the natural world follows from the nature of God, exactly like the theorems of geometry follow from the initial axioms, postuates, and definitions of the system. Wherever there is a cause, there is a reason, and vice versa.
  4. Hume (1711-1776) held that although there is no such thing as chance in the world, the idea of necessity arises from the fact that the experience of the constant conjunction of two things establishes the custom of expectation within us.
  5. Holbach (1723-1789) held that the world to be a system of material particles moving according to fixed laws of motion in such a way that necessity rules everywhere, free will is a delusion, and the sum of existence remains always the same even though the individuals and worlds form and disintegrate in fixed cycles.
  6. Laplace (1749-1827) considered the necessity of the world as all-encompassing of its past, present and future, so that a super-human genius whose intelligent is sufficiently vast to know all the forces acting in the universe and the disposition of the beings acted upon by these forces, this intelligence would be able to expressed in a single formula the movement of every star and atom; he would be able to predict the total future of the world from its present condition. Not having this information we must be proceed by probability; that is, the ratio the number of favorable cases to all possible cases.
3. Theological Necssity. When necessity is affirmed of God, God is considered to be a necessary Being.
  1. Aristotle's analysis led him to the conception of a necessary being, consisting of pure form or pure actuality (no potentiality). God stands in contrast to ordinary beings, which are contingent, containing matter or potentiality, and thus they can cease to exist.
  2. Avicenna (980-1037) distinguished between God as necessary in Himself, and things in the world as necessary since they are determined by external causes. According to Avicenna God is not a free creator; all things flow from Him in a definite hierarchy with all the rational necessity with which conclusions are drawn from premises. This necessity entered Avicenna's world and the world of Greek and Arabian philosophy in general because it is a rational world of intelligible essences. For essences are necessarily what they are in contrast to existences or facts that are contingent.
  3. Aquinas (1225-1274) accepted Aristotle's analysis and extended it. The necessity of the Being of God consists in the identity of His essence and His existence. And the contingency of the being of all created things consists in their essence not being identical with their existence.
  4. Duns Scotus (1266-1308) had accepted the Avicennian metaphysics of essence, but there was much in the Arabian's philosophy which he as a Christian had to reject. The problem that Scotus faced was to reconcile the freedom of God and the contingency of created things with these intelligible essences in the world and ideas in the divine mind. His solution was to assert the transcendence of God as infinite being above all essences, and to teach a radical voluntarism according to which all things, even the divine knowledge, are subject to God's will. God created the world by an act of freedom. It would have been possible for Him not to create it. His will was not inclined to do this by any higher principle, for it is itself the highest principle of divine acts. The existence of the world, far from being necessary, is the free effect of the free will of God. According to Scotus, Abelard (1079-1142) was wrong in assuming that God could create only what he created, and that what he created he created necessarily; and Aquinas (1225-1274) was in error when he teaches that the world is necessarily the best possible world. According to Scotus, God does not create all that He can create; on the contrary, He creates only what He desires to call into existence. Goodness, justice, and the moral law are absolute, only in so far as they were willed by God; if they were absolute independently of the divine will, God's power would be limited by a law not depending upon Him and He would no longer be the highest freedom or, consequently, the Supreme Being. In reality, the good is therefore the good, only because it is God's pleasure that it should be so. Thus God by virtue of His supreme freedom, could supersedes the moral law which now governs us by a new law, as He superseded the Mosaic law by the Gospel. In the creation as in the government of the world, God knows no other law, no other rule, no other principle, than His own freedom. If God is not absolutely free and if He is, as Aquinas claims, a being absolutely determined in His will by His supreme wisdom, then God would not be the Supreme Being, but His rationality would be God. Like God, man is free; the Fall did not deprive man of his free will; man has formal freedom, that is, he may will or not will; and he has material freedom, that is, he can will A, or will B (freedom of choice or indifference). These doctrines of Scotus are diametrically opposed to those of Augustine and the Pelegian tendencies which they implied was recognized by the Roman Church who failed to canonize him.
  5. Liebniz's (1646-1716) distinction between two types of necessity leads to the distinction between God as absolutely necessary and the things of the world as hypothetical necessary. As an absolutely necessary Being, God could create only the best possible of all worlds, and this world is governed by hypotheical necessity.
  6. The conception of God as a necessary Being is the basis of the Ontological Argument for the existence of God as put forth by Anselm (1033-1109), and others. Aquinas and Kant did not think that God's existence could be inferred from His essence.