Spencer Heath Archive

Item 1149

Typed article written by Heath while in law school. This article had some 75 sidebars, often several per paragraph, which were not transcribed but can be found in the Originals envelope.

1905 OR 1906

 

 

A THEORY OF KNOWLEDGE

 

Introductory

There is something singularly striking in the correspondence between the mind with its pro­cesses and activities and the world or cosmos with its processes and activities. It almost seems as though the human mind within might be a micro-cosmos modeled in plan and detail like the macro-cosmos without. And, indeed, if the Nebular and Evolutionary Theories be true, the human organism and the human mind are products of the same forces and the same causes that have formed and organized the cosmic whole, from the atom and the microscopic cell to the solar and the stellar systems.

     What wonder, then, that the actions of the thoughts so closely mock the actions of the cells and stars?

     The material of the nebula has developed into more or less coherent forms in the planetary systems, and the star mists, in confusion, may develop into other mighty systems in the aeons yet to come.

     The mind of man is organized upon a similar plan. Many of its processes and activities are uniform and constant, but he, too, has his star mists and confusion in his brain. Still, the forces there inherent seem destined to promote a grand progression and a never-ending gain.

     With this high destiny in store for man through the development towards a perfection of his powers which shall bring him into coherence and harmony with everything in every plane on every side, there can be no grander aspiration than to know and thereby to be — to gain the highest knowledge and thereby find the highest good. For goodness cannot be known but through knowledge, and in their more perfect forms the two con­verge and coalesce.

     To ask the question, Can man know truth? is to ask, Can man know right? Truth is the child of know­ledge and right is the child of truth. To ask whether man can know is to ask whether man can be, to abandon faith in truth and right and in wholesome development and organization.

Man’s percepts of what is not of himself and of what is of himself are his primest concepts. These are expressed by experience and in consciousness, and back of them we cannot go. He who denies the validity of experience and consciousness denies the base and root of all that man can do or know or be. He has no standing point from which to view the swing of cosmic law. Man can and does have knowledge, and all he knows springs from and has its roots deep down in the simple facts of experience and consciousness.

Even if these prime percepts should have no absolute or ultimate being, or if there should be no absolute reality in the objects of perception, as has

been claimed, the perceptions are the same, in kind at least, to all men’s minds. Even if knowledge and truth can have no being objective and apart from man, it is at least uniform and absolute so far as all mankind can know. And knowledge relates to man; he is an inseparable element, and knowledge cannot be viewed with reference to anything that man knows not of neither by particular experiences nor directly by con­sciousness. Any theory based on absoluteness or unknowableness transcends all experience and all consciousness and falls to the ground through sheer non-pertinency and inutility to man.

     The theory of knowledge to be outlined here takes for granted experience and consciousness, and that out of these come all rational knowledge and also the experimental confirmation of that knowledge.

If all general knowledge shall consist (as it must) in explanations of the laws and methods wherein all things have their being or by which they take their course or sequence, then, if there be any knowledge, there must be a knowledge of know­ledge, or of the laws and methods wherein knowledge has its being and by which it takes its course in its unfoldment to the human mind. It is of these laws and methods that this discussion will take account.

In view of the value of knowledge to man in its being the guide to doing and the key to the highest being and becoming, no apology seems neces­sary for undertaking to outline a true theory of knowledge or the method whereby the most certain truth is and can be known.

 

              Exposition of the Theory

 

All knowledge is of two kinds, direct knowledge and indirect knowledge. The first we cannot analyze. It is common to all men and consists in impressions and experiences and the consciousness of things as the objects of impressions and experiences and of the self as the subjective element in these. It also includes the common axiomatic percepts or intuitions.

he second is indirect and derivative. It is complex and therefore capable of analysis. It is not native to consciousness and makes no direct appeal thereto. It is based upon direct knowledge, but its development comes through processes of reason­ing and its verification through experiments. This indirect knowledge is what is commonly referred to as knowledge.

There are three great divisions or sources from which indirect or developed knowledge must be derived. The first is direct knowledge and consists in the axiomatic percepts — the consciousness of self and the consciousness of the objects of experience in observed phenomena or cognized facts without regard to their causes or explanations.

The second is logic or rational demonstration, the determinations of causes and relations by logic or by putting the question to the powers and activi­ties of the mind.

 The third is experimental proof by the observation of logically anticipated phenomena by putting the question to external nature.

These three, then, must be held well in mind. They are, first, the prime percepts of direct know­ledge, second, the logical demonstration of explana­tions or causes, and, third, the experimental proof. The elements of these three things will be taken up separately.

The elements of all phenomena are causal and resultant. The causal elements are always of two kinds, subjective and objective, and they are real as distinguished from the resultant elements which are relative or phenomenal.

Taking up, then, the first division, the elements of direct knowledge, or observed phenomena, are, as causal, the physical senses and axiomatic percepts, subjective, and external nature or condi­tions, objective. The resultant elements or the phenomenal consist in physical and mental activities, giving rise of physical adaptations and to mental con­cepts. The physical activities develop into life pro­cesses and into instincts, and these form the subject matter of physiology, biology and psychology. The life processes consist in the natural selection and organization of cells or particles which respond with the best adaptation to their environment. The instincts consist in the persistence, in somewhat permanent form, of the activities which have led to consist in natural selection and organization of cells or particles which respond with the best adaptation to their environment. The instincts consist in the persistence, in somewhat permanent form, of the activities which have led to natural selection and thus tended to preserve the life. This is a sort of blind, mechanical, as distinguished from rational, activity. The perfection of instincts would indeed be the perfection of adaptation, but instincts come slowly and painfully, and tend to persist even after they become useless or harmful, whereas reason is special and solvent, showing quickly the most fitting and subservient adaptation.

 

The mental activities are a special differentiation of the physical. They give rise to processes of demonstration which are the subject-matter of logic — the science of reason or the understanding.

 

Taking up now this second great division, or logic, its content is seen to be the instrument or method by which the being can predicate or anticipate much of the phenomena resulting from interactions between itself and its environment, and between the respective parts of each. The use of logic, it may be said, is to bring the being into a knowledge and realization of the highest coordination between itself and its parts in harmony with nature as a whole.

 

There are two methods of reasoning. The inductive method begins with a hypothesis in fact, based upon the percepts of direct knowledge. From particular known facts, as a hypothesis, the pro­cess leads to general causes or explanations of the facts, or to a general knowledge of their relations.      The deductive method, or the dogmatic, begins with a hypothesis in speculation. The process leads from assumed general causes or explanations to the parti­cular facts which would logically result from such assumed general causes.

     The inductive process derives the explanation from the known facts. This is the method of science. The deductive seeks to adapt the facts to an assumed explanation. This is the method of theology. The natural or normal method is the inductive. It begins with the facts of direct knowledge which are prime concepts. Particular knowledge always precedes general knowledge. Science reasons from the particular to the general. It is true that the process may sometimes be reversed, and here the deductive has a secondary value, but the inductive process must come first to afford a rational hypothesis. A speculative hypothesis is mere guess work, and conclusions drawn from it are no more valid than the speculation itself.

 

Now as to the elements of logic or rational demonstration, they also are causal and resultant. Here the subjective causal element is the rational part of the mind or organ of thought with its axio­matic percepts and its coordinated and related concepts. The objective causal element is that part of the mind or brain which has received the newly acquired or specially considered concept, which, in the first instance, was a phenomenal or resultant element.

The phenomenal or resultant element in this second division is a logical demonstration or series of related concepts which brings the new or special concept into congruent coordination with the mind.

 

Taking up the third great division or experi­mental proof, we find two general kinds of experiments, but no sharp line can be drawn between them. First, there are those in which the conditions of the experi­ment are under control of the investigator. Among these are laboratory experiments in chemistry, physics, mechanics, electricity, etc., experiments in mathematics, in objective analyses and graphical solutions. In all these experiments great care must be taken to produce and secure the essential conditions required in the rational demonstration.

Second, there are those experiments in which the conditions are not under control, but must be found in the regular operations of nature independent of any participation on the part of the investigator. Among these are experiments or observations on general cosmology, astronomy, meteorology, political economy, ethics, etc.

There are many instances in which the conditions are found in part in nature and supplied in part by the investigator. Among these are Franklin’s experi­ments with the kite, the various attempts at rain making and climate changing, and the breeding of ani­mals and plants, experimental legislation, etc. In all experiments great care must be taken to insure that the conditions observed are essentially the same as those required in the rational demonstration.

     In the experimental proof we have a process in external nature, rather than in the mind, but every real experiment must be preceded by a more or less perfect rational demonstration. We must have a definite rational question to ask before we can put the question to nature for an experimental answer. But in the experimental proof the mind plays a passive rather than an active part, hence the process will be considered with respect to nature as the subject and the mind as the object.

Here the subjective causal element consists of facts or conditions in the substance of external nature corresponding with the hypothesis of the rational demonstration. The objective causal element consists in the coordinated congruent succession of concepts comprising the rational demonstration which predicates the result of the experiment.

The phenomenal or resultant element consists in the effect produced by the experiment upon the rational demonstration. This effect will be verifica­tion or non-verification. In the ease of verification, it is the confirmation of logic by experiment in which each checks the other and eliminates the probability of error in either. In the case of non-verification, there is a failure of correspondence between logic and experiment, showing either an error in the rational demonstration — a violation of the laws of logic — or an error in the experiment in not securing the causes or condition assumed or required in the rational demon­stration, or one or more errors in both the rational demonstration and in the conditions of the experiment.

 

It has been the custom among logicians to regard one of these kinds of experimental proof as a method of reasoning. In those experiments in which the conditions have not been under control of the investigator,

they have called the experiment a reasoning process and labeled it the deductive method. It is not a reasoning process, but an experiment of observation in the light of a reasoning process already performed.

 

     For illustration, if one should observe the various shapes of trees and then reason about it, he might conclude that trees take their form from outward forces or causes rather than from any necessities inherent in themselves. This conclusion would be from an induction of logic. If he knew all the ele­ments contained in trees, as he knows of triangles and the like, the rational theory about trees might have been obvious without special confirmation by experiment. But in the case of trees he must resort to experiment for a further degree of certainty. Now, if he acts as an agent and takes the experiment in hand by the laboratory method, he bends over a young tree and observes the form which it takes under the force which he has imposed. No one would dream of calling this a process of logic or anything else but an experi­ment pure and simple, yet there is a process essentially the same as this which has been called a method of logic. Suppose our investigator had gone out into the forest and taken observation on a young tree upon which a larger one had fallen. Here the experiment would have been essentially the same though the conditions had not been at all under his control. This second observation is an example of what has been called deduction or the deductive method of logic. It is simply one of the forms of experiment.

Every experiment which tests a theory should be repeated many times in the widest possible fields and under the most widely varying non-essential condi­tions.

     We have now completed an analysis of the three divisions which comprise the present theory of knowledge: first, direct knowledge, second, rational demonstration, and third, experimental proof. When a theory has been derived from a basis in direct knowledge by a careful rational demonstration, it is then reasonably certain to be true. When it has been confirmed by one practical experiment, it is more than reasonably certain. When it has been further con­firmed by many experiments in many fields, surrounded by diverse, external or non-essential conditions, it becomes as perfect a certainty as anything can be to the mind of man. The whole indirect knowledge of man­kind consists of explanations of phenomena possessing these various degrees of certitude.

     There have been many speculations on the limits and possibilities of human knowledge. I believe knowledge can be, for all purposes, certain — that it is the next thing in certainty to being. I believe there are practically no limits to know­ledge, and that with the most perfect knowledge comes the most perfect development, the most perfect existence, the most perfect being.

     Briefly summarizing the theory here outlined, the basis of knowledge is found in observations or experiences without reference to their causes or

explanations; its development is found in the rational processes of the mind — processes having their starting point in the same kind of experiences which have organized the mind; it is confirmed by one practical experiment; it becomes for all purposes a certainty when confirmed by many and diverse practical experiments.

     In the various discoveries of knowledge, it is not claimed that the theory has perfectly uniform application. It is to be admitted that it is subject to many modifications in its details, in its applica­tion to special cases. The three great divisions upon which it is built are not claimed to have a precisely equal weight and bearing in all cases, but merely that each of them must enter in greater or less degree. They may sometimes be so closely related as to almost obscure the line of separation between them, as when mental concepts merge into processes, or when the general perceptions of observation pass quickly into definite scientific experiments. Where these different things are so closely connected in time or relation, their essential difference may at first escape detection, but analysis shows them in their several relations.

     Nothing that is known can be derived from what is not known. Truth cannot be derived from that which is not truth. Speculation is a dream, and like all dreams, it is without any objective content. It is a mere guess from the start. Experience is the prime concept. It has an objective side. It is the

one prime, indisputable fact. From it we can learn something of something. In it is the beginning of knowledge; from it proceeds rational knowledge, and by

it again is secured the perfection of knowledge in experimental certainty.

 

Test of the Theory

 

This theory of knowledge will now be assumed as fairly established. It yet remains to be tested by experiment, and to show how this theory has held good for the knowledge that mankind has acquired. A few examples will be given. We will select a few of the things which science holds as true and try to trace the method, conscious or unconscious, whereby these truths have become known.

Beginning with what may seem a very simple and certain order of truth, mathematical truth, we will cite a simple instance of how discoveries have been made in that line. The relations between the sides of a right tri-angle is a matter of very common know­ledge, but it is not direct knowledge. It has been acquired within historical times and none could have guessed its truth until after he had reasoned about it. When the discoverer of the pons asinorum worked out his rational demonstration, he had just developed that coordination of concepts which makes up a more or less perfect theory or demonstration. From the certainty and simplicity of the hypothesis this demonstration could be very conclusive, but it still remained to apply the test of experiment. It was tried upon triangles, large and small, isosceles and scalene. The sides were measured with scrupulous care and every test but confirmed all the others until there was nothing more certain than the principle of the pons asinorum.

In the same manner Newton and Liebnitz worked out an elaborate theory of the calculus. The theory was tested by practical experiment and solutions of the most complex practical problems were performed with marvelous facility and ease.

In chemistry, the theory of definite chemical quantities was worked out by Faraday and Dalton as a rational theory. The same great investigators applied the test of many practical experiments and the theory was well confirmed. Dalton worked out an elaborate theory of atoms to explain chemical pheno­mena, and the behavior of the elements under all practical experiments has tended to confirm this theory.

In physics, one of the great triumphs of science was attained in the theory of the mechanical equivalent of heat. Colding, Mayer, Joule and others, especially Colding, seized upon it as a rational theory, and each set to work in his own way to apply the test of prac­tical experiments. Here the experiments were carried out in the most widely diverse fields. Mayer, being a physician, investigated not only with regard to physical but also to physiological phenomena, in which heat was converted into mechanical force and mechanical force into heat. Joule also made the test by means of various machines and apparatus in which known mechanical force was converted by friction or other means into a measured quantity of heat. As a result of this theory, any quantities of heat or mechanical force can be expressed in exactly convert­ible terms.

In the field of astronomy the most striking confirmations of rational theories have occurred. After Newton had worked out his theory of gravitation as the force which rules the planets, suns and stars, he put the question to nature. He made calculations in the light of his theory to determine what motions the moon should take about the earth. Having determined these motions, he sought experimental confirmation for his theory by their comparison with the actual motions of the moon. The experiment failed and for a time the

whole theory was abandoned. But it was afterwards found that the distance to the center of the earth had been erroneously taken. The calculations were gone

over again upon the corrected data and the theory was found to fully predict the actual motions of the moon. Prom this /point/ on nature seemed more than willing to yield up her answers to the questions of experiment. The observations in the heavenly bodies confirmed in minutest detail the correctness of the rational theory. The planet Neptune was actually discovered and located as a rational necessity before it had ever been seen, and this presented probably the most striking confirmation that experiment has ever given to a theory.

     Taking up the Nebular Hypothesis, we have a theory based upon direct observations upon the astro­nomical systems. It is essentially a rational theory. It is not based on any observation of instances in which the whole process contemplated by the theory had been known to occur. It assumes only the general facts of direct observation upon the cosmic systems as they are now seen, and upon this a purely rational theory has been constructed to explain how these things came to be. The question of the theory has been put to nature in many ways. In the laboratory, masses of vaporous oil have been caused to condense and rotate in water, and small globules have been observed to break off and assume a planetary motion about the parent mass. In the depths of space nebulous masses are found. In some a nucleus can just be discerned; in others it appears more distinct, and passing on to other masses, they appear as nebulous stars, and finally as ordinary stars, groups of stars and systems. The whole process of change for any one mass has not been observed, but for the systems in general it has been observed, to use Prof. Ball’s illustration, in the same manner that we can observe the growth of trees in a forest, by comparing the trees of various ages which the forest contains at one time. To all the questions of experiment nature has never given an ambiguous, much less a negative, answer, and the Nebular Theory stands as a monument to one of the boldest of rational incursions upon the stolid secrets of the universe, supported by all the positive evidence, and accepted very generally by the scientific world.

     What has been said of the Nebular Theory in the domain of cosmogony may be repeated of Evolution in the sphere of cosmology. Indeed, by some writers, notably Mr. Spencer, the two are included under the general theory of evolution as comprehended by his well-known and very general definition of that theory.

The Theory of Evolution is held as a rationally conceived explanation of the general method or law under which all the processes of universal change have taken place and continue to take place. It is based upon the most general direct observations of nature and of the world, and derived from the necessities inherent in the logical part of the brain. The question of its truth may be put to nature in many ways. We may observe the answer in the formation of a crystal, in the organization of a homogeneous mass into differentiated parts having relations and forms corresponding to mathematical concepts of the mind. We may observe it in the development of organic structures from unorganized substance into differentiated parts having organic form and functional relations. And further we may observe it with refer­ence to organic types as developed from variations in organic forms. This may be carried on by the labora­tory method of the development of desired types of plants and animals by methodical selection and breeding. The process which in nature is generally too slow to be observed except by the presence of the various points or stages which go to make up the series, can be hastened and guided under the direction of man so that among domestic plants and animals he may view the actual processes which intervene between quite widely different structures and types. In this the test of experiment is brought to bear upon the theory of evolution. The theory predicts the results and the experiments seldom fail to attain them. So closely can the theory be aligned with the apparent changes which have taken place under nature, and so truly does it predict the results which may be obtained under the guidance of man, it has won for itself a very general acceptance by those who are interested in the development of a rational cosmology.

Turning now from the realm of nature which may be distinguished from that which includes the recipro­cal activities between the individuals of mankind, a passing view will be taken of the development of a few of the theories concerning the associations of mankind, which have been generally accepted as true:

The theory of Divine Right of Kings never had a sound logical defense. What hold it had was due to self-interest on the part of the governing power and its beneficiaries, and was the result of their physical and moral coercion upon the governed. The logical inadequacy of the theory was conclusively shown by Austin and thoroughly confirmed in Locke^’s famous confutation of Pilmer. These opposite logical views, however, have both been put to the test of practical experiment and humanity well knows the results. The experiments in divine right have generally been complete failures so far as the welfare of the people has been concerned, whereas the experiments in partial and one-sided democracies have had certainly a partial if not an invariable success. As the case stands today, the theory in its original form has little standing among the leading peoples of the world. As a rational theory it would not bear the test of analysis, and as a practical policy under the test of experiment, the logic of events has shown its inherent weakness.

With the theory of consent of the governed, the case has been very different. Here was a sound rational theory, so ably demonstrated by Locke and many others. The voice of reason, based upon the primest concepts of right, was especially clear and unmistakable, and it has been well sustained by the verdict of every experiment. In the same manner, many rational theories of a less general character have been developed in the science of government. Many of them have been tried, and many more probably will be tried. Those which are not in accord with reason can never stand the test of experiment, but those which have been rationally well founded may be expected to succeed and become permanent. It is noticeable that all of Bentham’s theories of government which have been tried have proved as ser­viceable as they were rational.

Leaving now the science of government, or politics, and turning to the science of wealth, or political economy, we find that much has been gained, and that much remains to be gained. This is pre­eminently a natural science. It deals with natural laws which operate upon mankind through the various phenomena of production and exchange. Like all other natural laws it is the province of man to bring him­self into harmony with their operations that they may be of benefit to him. The complex adaptations of mankind to the natural economic laws has been concur­rent with and necessary to the growth of peoples and the organization of governments. These natural laws cannot be suspended or perverted except by the inter­vention of government, and so the conquests of this, perhaps greatest of all sciences, are mainly directed against the perversion of natural economic laws by the pernicious distortion of the normal powers of government, which powers should be confined to the securing and guaranteeing of the free play of the natural moral laws and the economic laws, as revealed by the science of political economy.

When Adam Smith, the father, or perhaps the foster-father of the science, laid down his argument for free and unrestricted trade, he made a grand contribution to rational knowledge. So powerful was his demonstration that it has been accepted by nearly all thinkers and all colleges to the present day. It is opposed by demagogues and “business” politi­cians on the same old grounds of special interests that Smith so well combated over a hundred years ago. The theory of free trade has been tried in England and in the early history of our country, with enough success to verify its rational grounds, while its results between the several United States have been phenomenal. But it must fight its way against the powers of governments swayed by powerful special interests till an enlightened common sense shall secure its benefits for the common welfare.

So it is with the theory that in competition is the life of trade. This has been developed and proved by all economists of standing in the analytical as opposed to what we may call the hysterical school. As a rational theory it is well founded and elaborated. As to being tested by experiment, the principle is too natural, important and necessary ever to have been wholly suppressed. Its beneficent operations have been curtailed in many ways by various monopolies and other trade restrictions instituted or permitted by govern­ments. The experiment thus takes a negative character, and it has been found that whenever and wherever competition has not had the freest and fullest play, there the most harmful results have ensued. The practical results of the experimental application are so far reaching and important that it cannot be suspended without the direst consequences.

Entering finally the domain of morality or ethics, we will view a few of the theories which are here well established and accepted. The theory of personal rights — of the inviolability of the person against violence or murder — is founded on the most direct percepts of moral right and social well-being. The experience that the world has had with personal violence has been sufficient to confirm all the rational theories against it. Growing out of the theory of personal rights, or the rights of the indivi­dual to his person, is the theory of property rights, so clearly derived in this connection in the philosophy of Locke. The theory of the sacredness of just property is shown to be almost a corollary to the theory of personal rights, persons being the creators of property and having the same kind of right to it that they have to themselves. The theory is too palpable for rational contradiction, and when submitted to the test of prac­tical experiment, it is found that disregard of the principle is always accompanied by disorder and a primi­tive stage of development and happiness.

We will view just one more principle in the domain of ethics, the principle of intellectual rights or political and religious toleration. The recognition and adoption of this principle is even yet not so general as might be desired. In the lists of moral debate many and specious have been the arguments for the self-appointed sculptors who would mould to their dogmatic pattern the god-like reason of mankind. But from Bruno and Galileo down to Prof. Briggs and Father McGlynn, the stoutest champions of intellectual freedom have fought the battles for man­kind. For the last one hundred years or more, England has been the hotbed of intellectual revolt, and few who have observed the contest can say that the battle has not been to the really strong and to the right.

The principle of intellectual freedom is now admitted even in the camp of its one-time opponents themselves, and few there are who will meet the issue and oppose it before the world. As a rational theory, it was long ago accepted by the master minds, and it has been sustained too well in practice to admit of any possible doubt.

 

Conclusion

We have now made quite an extended survey of high points in intellectual progress. It would be well, if space permitted, to analyze these fully and in detail. In each of these winnings of the mind there has been a rational theory derived from the facts of direct knowledge of the senses and the intui­tions. The theory has been more or less definitely proved by rational demonstration, and when submitted to nature in the form of experiment, the answer has been decisive and complete. The principles of know­ledge laid down in the earlier part of this paper are now seen to have been the guides to what has been achieved.

     It still remains to test by its own tenets the theory of knowledge here outlined. The derivation of this theory of knowledge begins with the prime concept or intuition that there is such a thing as knowledge. This is a thing which may be observed and experienced without reference to its causes; it partakes of the nature of direct knowledge. To this direct knowledge there has been applied a logical or rational process to seek out the causes of knowledge and the manner of its unfoldment. This has been done by the analysis of the elements involved and their synthesis into a form and relation congruent with the mind.

     Having developed the rational theory, it remained to be tried by experiment. The laboratory method, obviously, could not be used, nor is it likely that some new truth could be discovered as required for the special purpose of confirming a general theory of knowledge. It has been necessary, therefore, to resort to that kind of experiment in which the conditions are not specially constructed and under control; and so, a broad view has been taken of various kinds of know­ledge that the world has gained, and the method of its discovery, we may hope, has been faithfully reviewed. The question has thus been put to nature in many forms and the replies have seemed to show that the knowledge of man has been secured through the principles predi­cated and developed by the theory herein given. There has always been common and direct knowledge as the objective basis of rational theories, and there has always been either many special or a general submission of the theories to the tests of experiment. The theory of knowledge here given, then, seems consistent with the methods by which the explanations which make up knowledge have been derived.

 

     It is gratifying to believe that the theory given is not only supported by the experience of the past, but that, in looking back upon it, the theory is seen to have been itself derived by the very method which it lays down. The principles which this theory sets forth have been followed in this exposition of the theory itself.

     Having adopted this theory of knowledge, I believe it may be applied with fruitful results, either as an instrument or as a test, in the special departments of science and the various fields of general research. It is with some difficulty that I have refrained from showing its bearings in some special directions where I hold opinions that are not generally accepted, but I have confined myself to the advocacy of one theory alone for this occasion. With this theory of knowledge as a guide, I believe it is possible to construct a complete general philosophy, a philosophy which will comprehend and unify the relations of all the sciences and will construct theories which, if not definitely proved by experiment, shall at least not be subject to logical refutation, and which will answer, with some degree of probability, every craving of the mind as to the origin, progress and destiny of man, and the nature and methods of the universe by and in which man is conditioned throughout his whole existence.