APPENDIX B

HOW WE ATTAIN TO THE KNOWLEDGE OF CERTAIN TRUTHS

(From the 1851 edition)

All teaching and reasoning take certain truths as granted. That the unequivocal, a priori affirmations of the reason are valid, for all the truths and principles thus affirmed, must be assumed and admitted; or every attempt to construct a science of any kind, or to attain to certain knowledge upon any subject, is vain and even preposterous. As I must commence my lectures on moral government by laying down certain moral postulates, or axioms, which are, a priori, affirmed by the reason, and therefore self-evident to all men when so stated as to be understood, I will spend a few moments in stating certain facts belonging more appropriately to the department of psychology. Theology is so related to psychology that the successful study of the former without a knowledge of the latter is impossible. Every theological system and every theological opinion assumes something as true in psychology. Theology is, to a great extent, the science of mind in its relations to moral law. God is a mind or spirit: all moral agents are in his image. Theology is the doctrine of God, comprehending His existence, attributes, relations, character, works, word, government (providential and moral), and, of course, it must embrace the facts of human nature and the science of moral agency. All theologians do and must assume the truth of some system of psychology and mental philosophy, and those who exclaim most loudly against metaphysics no less than others.

There is a distinction between the mind's knowing the truth and knowing that it knows it. Hence I begin by defining self-consciousness.

Self-consciousness is the mind's recognition of itself. It is the noticing of, or act of knowing, itself: its existence, attributes, acts, and states, with the attributes of liberty or necessity which characterize those acts and states. Of this, I shall frequently speak hereafter.

The revelations of self-consciousness

Self-consciousness reveals to us three primary faculties of mind which we call intellect, sensibility, and will. The intellect is the faculty of knowledge; the sensibility is the faculty or susceptibility of feeling; the will is the executive faculty, or the faculty of doing or acting. All thinking, perceiving, intuiting, reasoning, opining, forming notions or ideas, belong to the intellect.

Consciousness reveals the various functions of the intellect, and also of the sensibility and will. In this place, we shall attend only to the functions of the intellect, as our present business is to ascertain the methods by which the intellect arrives at its knowledges, which are given to us in self-consciousness.

Self-consciousness is, itself, of course, one of the functions of the intellect; and here it is in place to say that a revelation in consciousness is science and knowledge. What consciousness gives us we know. Its testimony is infallible and conclusive upon all subjects upon which it testifies.

Among other functions of the intellect, which I need not name, self-consciousness reveals the three-fold fundamental distinction of the sense, the reason, and the understanding.

Of the sense

The sense is the power that perceives sensation and brings it within the field of consciousness. Sensation is an impression made upon the sensibility by some object without, or some thought within the mind. The sense takes up, or perceives the sensation, and this perceived sensation is revealed in consciousness. If the sensation is from some object without the mind, as sound or color, the perception of it belongs to the outer sense. If from some thought, or mental exercise, the perception is of the inner sense. I have said that the testimony of consciousness is conclusive for all the facts given by its unequivocal testimony. We neither need, nor can we have, any higher evidence of the existence of a sensation than is given by consciousness.

Our first impressions, thoughts, and knowledge, are derived from sense. But knowledge derived purely from this source would, of necessity, be very limited.

Of the reason

Self-consciousness also reveals to us the reason or the a priori function of the intellect. The reason is that function of the intellect which immediately holds or intuits a class of truths which, from their nature, are not cognizable either by the understanding or the sense. Such, for example, is the mathematical, philosophical, and moral axioms and postulates. The reason gives laws and first principles. It gives the abstract, the necessary, the absolute, the infinite. It gives all its affirmations by a direct beholding or intuition, and not by induction or reasoning. The classes of truths given by this function of the intellect are self-evident. That is, the reason intuits or directly beholds them, as the faculty of sense intuits or directly beholds a sensation. Sense gives to consciousness the direct vision of a sensation, and therefore the existence of the sensation is certainly known to us. The reason gives to consciousness the direct vision of the class of truths of which it takes cognizance; and of the existence and validity of these truths we can no more doubt than of the existence of our sensations.

Between knowledge derived from sense and from reason there is a difference: in one case, consciousness gives us the sensation: it may be questioned whether the perceptions of the sense are a direct beholding of the object of the sensation, and consequently whether the object really exists and is the real archetype of the sensation. That the sensation exists we are certain, but whether that exists which we suppose to be the object and the cause of the sensation admits of doubt. The question is, does the sense immediately intuit or behold the object of the sensation? The fact that the report of sense cannot always be relied upon seems to show that the perception of sense is not an immediate beholding of the object of the sensation; sensation exists, this we know, that it has a cause we know; but that we rightly know the cause or object of the sensation we may not know.

But in regard to the intuitions of the reason, this faculty directly beholds the truths which it affirms. These truths are the objects of its intuitions. They are not received at second hand. They are not inferences nor inductions, they are not opinions, nor conjectures, or beliefs, but they are direct knowings. The truths given by this faculty are so directly seen and known that to doubt them is impossible. The reason, by virtue of its own laws, beholds them with open face in the light of their own evidence.

Of the understanding

The understanding is that function of the intellect that takes up, classifies and arranges the objects and truths of sensation under a law of classification and arrangement given by the reason, and thus forms notions and opinions and theories. The notions, opinions, and theories of the understanding may be erroneous, but there can be no error in the a priori intuitions of the reason. The knowledge of the understanding are so often the result of induction or reasoning, and fall so entirely short of a direct beholding, that they are often knowledge only in a modified and restricted sense.

Of the imagination, and the memory, etc., I need not speak in this place.

What has been said has, I trust, prepared the way for saying that the truths of theology arrange themselves under two heads: Truths which need proof and Truths which need no proof.

Truths which need proof

First. Of this class it may be said, in general, that to it belong all truths which are not directly intuited by some function of the intellect in the light of their own evidence.

Every truth that must be arrived at by reasoning or induction, every truth that is attained to by other testimony than that of direct beholding, perceiving, intuiting, or cognizing, is a truth belonging to the class that needs proof.

Second. Truths of demonstration belong to the class that needs proof. When truths of demonstration are truly demonstrated by any mind, it certainly knows them to be true, and affirms that the contrary cannot possibly be true. To possess the mind of others with those truths, we must lead them through the process of demonstration. When we have done so, they cannot but see the truth demonstrated. The human mind will not ordinarily receive and rest in a truth of demonstration until it has demonstrated it. This it often does without recognizing the process of demonstration. The laws of knowledge are physical. The laws of logic are inherent in every mind; but in various states of development in different minds. If a truth which needs demonstration, and which is capable of demonstration, is barely announced and not demonstrated, the mind feels a dissatisfaction and does not rest short of the demonstration of which it feels the necessity. It is therefore of little use to dogmatize, when we ought to reason, demonstrate, and explain. In all cases of truths not self-evident, or of truths needing proof, religious teachers should understand and comply with the logical conditions of knowledge and rational belief; they tempt God when they merely dogmatize where they ought to reason, explain, and prove, throwing the responsibility of producing conviction and faith upon the sovereignty of God. God convinces and produces faith, not by the overthrow of, but in accordance with, the fixed laws of mind. It is therefore absurd and ridiculous to dogmatize and assert, when explanation, illustration, and proof are possible and demanded by the laws of the intellect. To do this, and then leave it with God to make the people understand and believe, may be at present convenient for us, but if it be not death to our auditors, no thanks are due to us. We are bound to inquire into what class a truth belongs, whether it be a truth which, from its nature and the laws of mind, needs to be illustrated or proved. If it does, we have n right merely to assert it, when it has not been proved. Let us comply with the necessary conditions of a rational conviction and then leave the event with God.

To the class of truths that need proof belong those of divine revelation.

All truths known to man are divinely revealed to him in some sense, but I here speak of truths revealed to man by the inspiration of the Holy Spirit. The Bible announces many self-evident truths and many truths of demonstration. These may or might be known, at least many of them, irrespective of the inspiration of the Holy Spirit. But the class of truths of which I here speak rest wholly upon the testimony of God and are truths of pure inspiration. Some of these truths are above reason in the sense that the reason can, a priori, neither affirm nor deny them.

When it is ascertained that God has asserted them, the mind needs no other evidence of their truth, because by a necessary law of the intellect all men affirm the veracity of God. But for this necessary law of the intellect, men could not rest upon the simple testimony of God, but would ask for evidence that God is to be believed. But such is the nature of mind, as constituted by the Creator, that no moral agent needs proof that God's testimony ought to be received. Let it be once settled that God has declared a fact or a truth, and this is, with every moral agent, all the evidence he needs.

The reason, from its own laws, affirms the perfect veracity of God, and although the truth announced may be such that the reason, a priori, can neither affirm or deny it, yet when asserted by God, the reason irresistibly affirms that God's testimony ought to be received.

These truths need proof in the sense that it needs to be shown that they were given by a divine inspiration. This fact demonstrated, the truths themselves need only to be understood, and the mind necessarily affirms its obligation to believe them.

My present object more particularly is to notice:

Truths which need no proof

These are a priori truths of reason and truths of sense; that is, they are truths that need no proof because they are directly intuited or beheld by one of these faculties.

The a priori truths of reason may be classed under the heads of first truths: self-evident truths which are necessary and universal: and self-evident truths not necessary and universal.

First truths have the following attributes.

(1) They are absolute or necessary truths in the sense that the reason affirms that they must be true. Every event must have an adequate cause. Space must be. It is impossible that it should not be, whether any thing else were or not. Time must be, whether there were any events to succeed each other in time or not. Thus necessity is an attribute of this class.

(2) Universality is an attribute of a first truth. That is, to truths of this class there can be no exception. Every event must have a cause, there can be no event without a cause.

(3) First truths are truths of necessary and universal knowledge. That is, they are not merely knowable, but they are known to all moral agents by a necessary law of their intellect.

That space and time are, and must be, that every event has and must have a cause, and such like truths, are universally known and assumed by every moral agent whether the terms in which they are stated have ever been so much as heard by him or not. This last is the characteristic that distinguished first truths from others merely self-evident, of which we shall soon speak.

(4) First truths are, of course, self-evident. That is, they are universally directly beheld in the light of their own evidence.

(5) First truths are truths of the pure reason, and of course truths of certain knowledge. They are universally known with such certainty as to render it impossible for any moral agent to deny, forget, or practically overlook them. Although they may be denied in theory, they are always, and necessarily, recognized in practice.

No moral agent, for example, can, by any possibility, practically deny, or forget, or overlook the first truths that time and space exist and must exist, that every event has and must have a cause.

It is, therefore, always to be remembered that first truths are universally assumed and known, and in all our teachings, and in all our inquiries we are to take the first truths of reason for granted. It is preposterous to attempt to prove them, for the reason that we necessarily assume them as the basis and condition of all reasoning.

The mind arrives at a knowledge of these truths by directly and necessarily beholding them, upon condition of its first perceiving their logical condition. The mind beholds or attains to the conception of an event. Upon this conception it instantly assumes, whether it thinks of the assumption or not, that this event had, and that every event must have, a cause.

The mind perceives or has the notion of body. This conception necessarily develops the first truth, space is and must be.

The mind beholds or conceives of succession; and this beholding or conception necessarily develops the first truth, time is and must be.

As we proceed we shall notice divers truths which belong to this class, some of which, in theory, have been denied. Nevertheless, in their practical judgments, all men have admitted them and given as high evidence of their knowing them as they do of knowing their own existence.

Suppose, for example, that the law of causality should not be, at all times or at any time, a subject of distinct thought and attention. Suppose that the proposition, in words, should never be in the mind, that "every event must have a cause," or that this proposition should be denied. Still the truth is there in the form of absolute knowledge, a necessary assumption, an a priori affirmation, and the mind has so firm a hold of it as to be utterly unable to overlook or forget or practically deny it. Every mind has it as a certain knowledge long before it can understand the language in which it is expressed, and no statement or evidence whatever can give the mind any firmer conviction of its truth than it had from necessity at first. This is true of all the truths of this class. They are always, and necessarily, assumed by all moral agents, whether distinctly thought of or not. And for the most part this class of truths are assumed, without being frequently, or at least without being generally, the object of thought or direct attention. The mind assumes them without a distinct consciousness of the assumption. For example, we act every moment, and judge, and reason, and believe, upon the assumption that every event must have a cause, and yet we are not conscious of thinking of this truth, nor that we assume it, until something calls the attention to it.

First truths of reason, then, let it be distinctly remembered, are always and necessarily assumed, though they may be seldom thought of. They are universally known before the words are understood by which they may be expressed; and although they may never be expressed in a formal proposition, yet the mind has as certain a knowledge of them as it has of its own existence.

All reasoning proceeds upon the assumption of these truths. It must do so of necessity. It is preposterous to attempt to prove first truths to a moral agent; for, being a moral agent, he must absolutely know them already, and if he did not, in no possible way could he be put in possession of them except by presenting to his perception the chronological condition of their development, and in no case could any thing else be needed, for upon the occurrence of this perception, the assumption or development follows by a law of absolute and universal necessity. And until these truths are actually developed, no being can be a moral agent.

There is no reasoning with one who calls in question the first truths of reason and demands proof of them. All reasoning must, from the nature of mind and the laws of reasoning, assume the first-truths of reason as certain, and admitted, and as the a priori condition of all logical deduction and demonstration. Some one of these must be assumed as true, directly or indirectly, in every syllogism and in every demonstration.

In all our future investigations we shall have abundant occasion for the application and illustration of what has now been said of first truths of reason. If, at any stage of our progress, we light upon a truth of this class, let it be borne in mind that the nature of the truth is the preclusion, or, as lawyers would express it, the estoppel of all controversy.

To deny the reality of this class of truths is to deny the validity of our most perfect knowledge. The only question to be settled is, does the truth in question belong to this class? There are many truths which men, all sane men, certainly know, of which they not only seldom think, but which, in theory, they strenuously deny.

2. The second class of truths that need no proof are self-evident truths, possessing the attributes of necessity and universality. Of these truths, I remark:

(1) That they, like first truths, are affirmed by the pure reason, and not by the understanding, nor the sense.

(2) They are affirmed, like first truths, a priori; that is, they are directly beheld or intuited, and not attained to by evidence or induction.

(3) They are truths of universal and necessary affirmation, when so stated to be understood. By a law of the reason, all sane men must admit and affirm them in the light of their own evidence, whenever they are understood.

This class, although self-evident when presented to the mind, are not, like first truths, universally and necessarily known to all moral agents. The mathematical axioms and first principles, the a priori grounds and principles of all science, belong to this class.

(4) They are, like first truths, universal in the sense that there is no exception to them.

(5) They are necessary truths. That is, the reason affirms, not merely that they are, but that they must be, true; that these truths cannot but be. The abstract, the infinite, belong to this class.

To compel other minds to admit this class of truths, we need only to frame so perspicuous a statement of them as to cause them to be distinctly perceived or understood. This being done, all sound minds irresistibly affirm them, whether the heart is, or is not, honest enough to admit the conviction.

3. A third class of truths that need no proof are truths of rational intuition, ut possess not the attributes of universality and necessity.

Our own existence, personality, personal identity, etc, belong to this class. These truths are intuited by the reason, are self-evident, and given, as such, in consciousness; they are known to self, without proof, and cannot be doubted. They are at first developed by sensation, but not inferred from it.

Suppose a sensation to be perceived by the sense, all that could be logically inferred from this is that there is some subject of this sensation, but that I exist, and am the subject of this sensation, does not logically appear. Sensation first awakens the mind to self-consciousness; that is, a sensation of some kind first arouses the attention of the mind to the facts of its own existence and personal identity. These truths are directly beheld and affirmed. The mind does not say, I feel, or I think, and therefore I am, for this is a mere sophism; it is to assume the existence of the I as the subject of feeling, and afterwards to infer the existence of the I from the feeling or sensation.

4. A fourth class of truths that need no proof are sensations. It has been already remarked that all sensations given by consciousness are self-evident to the subject of them. Whether I ascribe my sensations to their real cause may admit of doubt, but that the sensation is real there can be no doubt. The testimony of the sense is valid for that which it immediately beholds or intuits, that is, for the reality of the sensation. The judgment may err by ascribing the sensation to the wrong cause.

But I must not proceed further with this statement; my design has been not to enter too minutely into nice metaphysical distinctions, nor by any means to exhaust the subject of this lecture, but only to fix attention upon the distinctions upon which I have insisted for the purpose of precluding all irrelevant and preposterous discussions about the validity of first and self-evident truths. I must assume that you possess some knowledge of psychology and of mental philosophy, and leave to your convenience a more thorough and extended examination of the subject but hinted at in this lecture.

Enough, I trust, has been said to prepare your minds for the introduction of the great and fundamental axioms which lie at the foundation of all our ideas of morality and religion. Our next lecture will present the nature and attributes of moral law. We shall proceed in the light of the a priori affirmations of the reason, in postulating its nature and its attributes. Having attained to a firm footing upon these points, we shall be naturally conducted by reason and revelation to our ultimate conclusions.