Belief (be and lyian, to hold dear), that state of the mind by which it assents to propositions, not by reason of their intrinsic evidence, but because of authority. Though the term is commonly used in ordinary language, as well as in much philosophical writing, to cover a great many states of mind, the quasi-definition advanced is probably the best calculated to differentiate belief from all other forms of mental assent. In framing it, respect is paid to the motive of the assent rather than to its nature; for, since intellectual assent is of its nature simple and indivisible, no differentiae proximae can be assigned, by which it could be separated into various species. As the objects of belief, also, are of a nature similar to those of knowledge, opinion, and doubt, so, again, no criterion of division can be found in them (as in the case of the objects of separate faculties) to distinguish it from other mental states. St. Thomas Aquinas qualifies his definition of faith with the addition of the note of certainty (Summa, I-II, Q. i, a. 4). Though he treats of faith as a theological virtue in the article cited, his words may well be extended to include belief as a purely natural state of the mind. It will thus be seen to cover intellectual assent to truths accepted on authority either human or Divine. In the former case belief may be designated by the synonym credence; in the latter the more usual term is faith. Often, also, belief is used in the sense of fiducia, or trust; and this especially in Protestant theology as a substitute for faith. By the definition given above we are enabled to distinguish belief (I) from intelligence, in that the truth of the fact or proposition believed is not seen intuitively; (2) from science or knowledge, since there is no question of resolving it into its first principles; (3) from doubt, because belief is an assent and positive; (4) from opinion and conjecture, in which the assent is not complete.
Belief, however, as has already been noted, is often indiscriminately used for these and for other states of mind from which for the sake of accuracy it should be as carefully distinguished as is possible. Though we may know a thing and at the same time believe it (as in the case of the existence of God, which is a natural verity as well as a revealed truth), it is in the interest of clearness that we should keep to the distinction drawn and not confound belief and knowledge, because of the fact that the same truth may simultaneously be the object of both. But there is another very general use of the term belief in which it is taken to designate assent complete enough to exclude any practical doubt and yet distinguishable from the assent of knowledge. In this use no account is taken of authority. We have many convictions resting upon evidence that is not sufficiently clearly presented to our mind to enable us to say we know, but abundantly sufficient for us to produce a practically unqualified assent. While this would seem to fall under the Scholastic head of opinion, it is the point about which has turned the controversy that has been waged since David Hume brought the question into prominence upon the philosophic issue. Briefly, to select a certain number of typical writers for examination, the issues involved are these. How far do we believe—in the sense of trusting our natural faculties in their reports and judgments; and in how far can we be said to know? Hume, in accordance with his sensistic principles, would restrict our knowledge to purely ideal truths. We are capable of knowing, according to the Scotch sceptic, such ideal principles as those of mathematics, together with the conclusions that are derived from them. But our attribution of an objective reality to what we imagine to be the causes of sensations is a belief. So also are such judgments as that of the principle of causality. We cannot be said to know, but to believe, that there is actually such a relation as that of effect to cause. We believe this, and other similar truths, because of a peculiar character of vivacity, solidity, firmness, or steadiness attaching to our conceptions of them. The division is an arbitrary one and the explanation offered as to the nature of belief unsatisfactory and insufficient. Similarly, James Mill would have the assent given to the objective reality of beings a belief. With him the occasion of the belief is the association of ideas: or, rather, as he wrongly states it, the association of ideas is the belief. If belief is a state of mind at all, it can scarcely be described as an association of ideas. Such an association could at most be considered as a cause of the belief. John Stuart Mill in his note to his father’s Analysis, makes belief a primitive fact. It is impossible to analyze it. Locke, though he deals at some length with belief, does not try to analyze it or do more than assign objects to it and investigate the grounds of credibility. Alexander Bain originally held belief to be a function of the will rather than a state of the intellect. In his opinion it was the development of the will under the pursuit of immediate ends. Later, he modified this opinion, and, while retaining the essentially volitional and emotional character, or tendency, as causes, relegated the act of belief itself to the intellectual part of man’s nature. Father Maher, S.J., whose admirable treatment of the whole subject ought to be consulted, advances an acute criticism of Dr. Bain’s position. He points out (I) that readiness to act is a test of belief, not the belief itself; (2) that belief is generally not active but characteristically passive; (3) that primitive credulity, which Bain makes a chief factor in belief, involves a vicious circle, explaining, as it does, belief by credulity or believing.
A not inconsiderable part of the “Grammar of Assent” is concerned with this subject, though hardly dealing with the problem on the foregoing lines. In his treatment of “Simple Assent”, and especially in sections 4 and 5 of Chapter iv, Par. 1, Cardinal Newman’s view can be found. He calls the notional assent that we give to first principles presumption. We cannot be said to trust our powers of reasoning or memory as faculties, though we may be supposed to have a trust in any one of their particular acts. That external nature exists is a first principle and is founded upon an instinct. The use of the term is justified by the consideration that the brute creation also possesses it. Further, “the belief in causation” is one of these presumptions, and the assent to it notional. But, on the other hand, “we believe without any doubt that we exist; that we have an individuality and identity all our own; that we have a present sense of good and evil, of a right and a wrong…” Again: “Assent on reasonings not demonstrative is too widely recognized an act to be irrational, unless man’s nature is irrational, too familiar to the prudent and clear-minded to be an infirmity or an extravagance.” It will be noted that Newman (I) justifies belief as an assent because based on a common use of the rational faculty. Demonstrative grounds may be lacking, but the conviction is none the less neither an infirmity nor an extravagance, but rational. (2) He groups belief and knowledge together under the heading of presumption without drawing any hard and fast line between them. And indeed, from the point of view of mere assent, there is nothing psychological by which they are to be distinguished: since assent itself, as has been noted, is a simple and ultimate fact. The difference lies elsewhere. In this broader sense of belief, it is to be found in the antecedent cause of the assent. For knowledge there will be explicit, for belief implicit, intuition or evidence.
Of German philosophers who have treated this topic, Germar, Fechner, and Ulrici may be consulted. The first limits belief to a conscious assent arising from fact; that is, an assent given without consciousness of its causes or grounds. In the case where the causes or grounds become actual factors in the consciousness, the belief rises to the dignity of knowledge. Kant’s view naturally has belief as the necessitated result of the practical reason. It is to be considered epistemologically rather than psychologically. We believe in such truths as are necessitated by the exigencies of our moral nature. And these truths have necessary validity on account of the requirements of that moral nature. We need motives upon which to act. Such beliefs are practical and lead to action. All natural truths that we accept on belief might conceivably be accepted as truths of knowledge. The implicit may unfold and become explicit. This frequently happens in ordinary experience. Evidence may be adduced to prove assertions. Similarly, any truth of knowledge may be accepted as belief. What is said to be known to one individual may be, and often is, accepted upon his testimony by another.
A great variety of factors may play their part in the genesis of belief. We are accustomed to assent to propositions that we cannot be said to know, on account of many different causes. Some of them are often inadequate and even frivolous. We frequently discover that our beliefs rest ca no stable foundation, that they must be reconstructed or done away with altogether. The ordinary reasons upon which belief may be based can be reduced to two: testimony and the partial evidence of reason. A third class of causes of belief is sometimes added. Feeling, desire, and the wish to believe have been noted as antecedent causes of the act of assent. But that feeling, desire, or the wish to believe is a direct antecedent is open to discussion. It cannot be denied that many so-called beliefs, more properly described, perhaps, as trust or hope, have their immediate origin in feelings or wishes; but, as a rule, they seem not to be capable of bearing any real strain; whereas we are accustomed to consider that belief is one of the most unchangeable of mental states. Where these antecedents work indirectly through the election of the will, to which reference is made below, belief may issue as a firm and certain assent. (I) Testimony is a valid and satisfactory cause of assent provided is possess the necessary note of authority, which is the sole direct antecedent of the ensuing belief. Our ultimate witness must know his facts or truths and be veracious in his presentation of them. Intermediate witnesses must have accurately preserved the form of the original testimony. In the case of human testimony the ordinary rules of prudence will naturally be applied before giving credence to its statements. Once, however, the question of knowledge and veracity is settled, belief may validly issue and an assent be given as to a certainty. Of course there is room also for doubt or for opinion, as the credentials of the authority itself may vary almost indefinitely. But there is a further class of truths believed upon testimony that does not fall within the scope of natural investigation and inquiry. The supersensible, supra-intellectual truths of revelation, at any rate in the present state of man’s existence, cannot be said to be assented to either on account of an intuition of their nature or because of any strict process of demonstration of their validity. They are neither evident in themselves nor in their principles. The assent to such truths is of the same nature as that given to truths believed naturally. Only here the authority motiving it is not human but Divine. Acts of assent on such authority are known as acts of faith and, theologically speaking, connote the assistance of grace. They are, nonetheless, intellectual acts, in the eliciting of which the will has its part to play, just as are those in which assent is given to the authoritative utterances of credible human witnesses. With regard to the nature of this authority upon which such supernatural truths are assented to in faith, it is sufficient to indicate that God‘s knowledge is infinite and His veracity absolute. (2) The partial evidence of reason has already been touched upon. It may be noted, however, that the evidence may be relative either relatively or absolutely. In the first case we may have recourse to the authority of those who know for our belief, or base it for ourselves upon such evidence as is forthcoming. In the second, as is the case with much of the teaching of science and philosophy, the whole human race can have no more than a strictly so-called belief in it. Probable opinions, conjectures, obscured or partially recalled memories, or any truths or facts of which we have not a consciously evidential grasp, are the main objects of a belief resultant upon partial evidence. In this its distinction from knowledge lies. We are said to know intuitional truths as well as all those that are indirectly evident in their principles. We know all facts and truths of our own personal experience, whether of consciousness or of objective nature. Similarly, we know the truth of the reports of memory that come clearly and distinctly into consciousness. Nor is it necessary, with Hamilton, to have recourse to an initial belief or trust as implied in all knowledge. We cannot properly be said to trust our faculties. We do not believe evident truth. (3) With the two immediate causes of belief already noted, the action of the will must also be alluded to. Under this head emotion, feeling, and desire may conveniently be grouped, since they play an important, though indirect, part in motiving assents through the election of the will and so causing belief. The action of the will referred to is observed especially in a selection of the data to be examined and approved by the intellect. Where there are several sets of evidences or partial arguments, for and against, the will is said to cause belief in the sense of directing the intellect to examine the particular set of evidences or arguments in favor of the resultant assent and to neglect all that might be urged against it. In this case, however, the belief can easily be referred to the partial evidence of reason, in that as a rational, rather than a volitional act, it is due to the actual considerations before the mind. Whether these are voluntarily restricted or incomplete from the very nature of the case, does not alter the fact that the assent is given because of the partial evidence they furnish. In faith the meritorious nature of the act of belief is referred to this elective action of the will.
The effects of belief may be summed up generally under the head of action or movement, though all beliefs are not of their nature operative. Indeed, it would seem to depend more on the nature of the content of the belief than upon the act of believing. As with certain truths of knowledge, there are beliefs that leave us unmoved and even tend to restrict and prevent rather than instigate to action. The distinction drawn between the assents of knowledge and belief cannot be said to be observed at all closely in practice, where they are frequently confused. It is none the less undoubtedly felt to exist, and, upon analysis of the antecedents, the one can readily be distinguished from the other. It is found that most of the practical affairs of ordinary life depend entirely upon beliefs. In the vast majority of cases in which action is called for it is impossible to have strictly so-called knowledge upon which to act. In such cases belief readily supplies its place, growing stronger as it is justified by the event. Without it, as a practical incentive to action and a justification of it, social intercourse would be an impossibility. Such things as our estimates of the character of our friends, of the probity of those with whom we transact business, are examples of the beliefs that play so large and so necessary a part in our lives. In their own subject-matter they are on a par with the reasonable beliefs of science and philosophy—founded, as are hypotheses and theories, upon practically sufficient, yet indemonstrative and incomplete data.