Commentary on Romans; Systematic Theology

Atheism is the denial of an extramundane personal God. In saying that Materialism is Atheism, it is not meant that all Materialists are atheists. Some, as for example, Dr. Priestley, confine the application of their principles to the existing order of things. They admit the being of God to whom they refer the creation of the world. The number, however, of such illogical Materialists is small. Leaving out of view these exceptional cases, the philosophers of this school may be divided into three classes, —

(1.) Avowed atheists. To this class belong the Epicureans; the French skeptics of the last century; the Positivists; and a large part of the physicists of the present generation, especially in Europe. (2.) Those who repudiate the charge of atheism, because they admit the necessary existence of an inscrutable force. But inscrutable force is not God. In rejecting the doctrine of an extramundane Spirit, self-conscious, intelligent, and voluntary, the First Cause of all things, they reject Theism; and the denial of Theism is Atheism. (3.) Those whose principles involve the denial of an extramundane God. To this class belong all those who deny the distinction between matter and mind; who deny the "supersensual," and "supernatural," who affirm that physical force is the only kind of force of which we have any knowledge; and who maintain that thought is in such a sense a product of the brain, that where there is no brain there can be no thought. Büchner, who although an avowed atheist, is, as to this point, a fair representative of the whole school, says that the fundamental principle (der oberste Grundsatz) of our philosophy is, "No matter without force; and no force without matter." "A spirit without a body," he adds, "is as unthinkable as electricity or magnetism without the matter of which they are affections."¹ This he makes the ground of his argument to prove the impossibility of the existence of the soul after death. The principle, if admitted, is equally conclusive against the existence of God. As Materialism leaves us no God to reverence and trust, no Being to whom we are responsible; and as it denies any conscious existence after death, it can be adopted only on the sacrifice of the higher attributes of our nature; and its whole tendency must be to demoralize and degrade.

Besides the considerations urged above against Materialism as a general theory, it may be proper to say a few words in reference to its modern scientific form. It is admitted that it is the province of scientific men to discuss scientific questions; and that much injury to the cause of truth has followed the attempts of men not devoted to such pursuits, undertaking to adjudicate in such cases. Physicists are wont to take high ground on this subject, and to warn off as intruders all metaphysicians and theologians, all who are devoted to the study of the supersensuous and the supernatural. They are not allowed to be heard on questions of science. The rule must work both ways. If metaphysicians and theologians must be silent on matters of science, then scientific men devoted to the study of the sensuous, are not entitled to be dictatorial in what regards the supersensuous. A man may be so habituated to deal with quantity and number, as to become incapable of appreciating beauty or moral truth. In like manner a man may be so devoted to the examination of what his senses reveal, as to come to believe that the sensible alone is true and real. The senses have their rights, and so have reason and conscience; and the votaries of sense are not entitled to claim the whole domain of knowledge as exclusively their own.

While, therefore, it is conceded that it belongs specially to scientific men to deal with scientific subjects, yet other classes have some rights which are not to be denied. They have the right to judge for themselves on the validity of the arguments of scientific men; and they have the right to appeal from one scientific man to another, and from the few to the many. So far as the correlation of physical and vital forces is concerned, it is not only a new doctrine, but as yet is adopted only by "advanced thinkers," as they are called, and call themselves. Dr. H. B. Jones, F. R. S., one of the more modest advocates of the doctrine,² says, "We are only just entering upon the inquiry how far our ideas of conservation and correlation of energy can be extended to the biological sciences." And certain it is that the leading men of science, both in Europe and America, are firm believers in vital and mental forces, as distinct in kind, from all physical forces operative in the inorganic world.

The Arguments for such Correlation are Invalid.

It has already been stated on the authority of the advocates of the theory, that their first and most important argument in its support is from analogy. The physical forces are all correlated; one is convertible into either of the others; all may be resolved into motion. This creates, as it is said, a strong presumption, that all force, whatever its phenomena, is essentially the same thing. If one kind of motion is heat, another electricity, another light, it is fair to infer that vitality is only another kind of motion, and thought and feeling another. As there is no reason for assuming a specific force for light, and another for heat, therefore it is unnecessary, and unphilosophical, to assume a specific kind of force to account for vital or mental phenomena. Prof. Barker of Yale College, says,³ "Today, as truly as seventy-five years ago when Humboldt wrote, the mysterious and awful phenomena of life, are commonly attributed to some controlling agent residing in the organism — to some independent presiding deity, holding it in absolute subjection." This presiding agent is called "vital fluid," "materia vitæ diffusa," "vital force." "All these names," he adds, "assume the existence of a material or immaterial something, more or less separable from the material body, and more or less identical with the mind or soul, which is the cause of the phenomena of living beings. But as science moved irresistibly onward, and it became evident that the forces of inorganic nature were neither deities nor imponderable fluids, separable from matter, but were simple affections of it, analogy demanded a like concession in behalf of vital force. From the notion that the effects of heat were due to an imponderable fluid called caloric, discovery passed to the conviction that heat was but a motion of material particles, and hence inseparable from matter; to a like assumption concerning vitality [namely, that it also is but a motion of material particles], it was now but a step. The more advanced thinkers in science of today, therefore, look upon the life of the living form as inseparable from its substance, and believe that the former is purely phenomenal, and only a manifestation of the latter. Denying the existence of a special vital force as such, they retain the term only to express the sum of the phenomena of living beings."

The argument from analogy is presented, as we have seen, in another form, by Huxley and others. The properties of water are very different from those of the hydrogen and oxygen of which it s composed. Yet no one supposes that those properties are due to anything else than the material composition of the water itself. So also the phenomena of living matter, and of the human brain, are very different from those of the elements which enter into their constitution; but this affords no presumption that there is any "vital force" or "mind" to account for this difference any more than the peculiar properties of water justify the assumption of the existence of anything distinct from its material element. Vitality and mind, we are told, have no better philosophical status than aquosity.

Dr. Stirling⁴ states the case thus: "If it is by its mere chemical and physical structure that water exhibits certain properties called aqueous, it is also by its mere chemical and physical structure that protoplasm exhibits certain properties called vital. All that is necessary in either case is, 'under certain conditions,' to bring the chemical constituents together. If water is a molecular complication, protoplasm is equally a molecular complication, and for the description of the one or the other, there is no change of language required. A new substance with new qualities results in precisely the same way here, as a new substance with new qualities there; and the derivative qualities are not more different from the primitive qualities in the one instance, than the derivative qualities are different from the primitive qualities in the other. Lastly, the modus operandi of preëxistent protoplasm is not more unintelligible than that of the electric spark. The conclusion is irresistible, then, that all protoplasm being reciprocally convertible, and consequently identical, the properties it displays, vitality and intellect included, are as much the result of molecular constitution, as those of water itself." This analogy is two-fold; having reference to chemical composition on the one hand, and to the antecedent stimulus which determines it on the other. "As regards chemical composition, we are asked, by virtue of the analogy obtaining, to identify, as equally simple instances of it, protoplasm here and water there; and, as it regards the stimulus in question, we are asked to admit the action of the electric spark in the one case to be quite analogous to the action of preëxisting protoplasm in the other."

In answer to this argument Dr. Stirling goes on to show that the analogy holds only as to chemical and physical properties. "One step farther and we see not only that protoplasm has, like water, a chemical and physical structure; but that, unlike water, it has also an organized or organic structure. Now this, on the part of protoplasm, is a possession in excess; and with relation to that excess there can be no grounds for analogy." "Living protoplasm, namely, is identical with dead protoplasm," says Dr. Stirling, "only so far as its chemistry is concerned (if even so much as that); and it is quite evident, consequently, that difference between the two cannot depend on that in which they are identical — cannot depend on the chemistry. Life, then, is no affair of chemical and physical structure, and must find its explanation in something else. It is thus that, lifted high enough, the light of the analogy between water and protoplasm is seen to go out."⁵ Water and its elements, hydrogen and oxygen, are as to the kind of power which they exhibit on a level. "But not so protoplasm, where, with preservation of the chemical and physical likeness there is the addition of the unlikeness of life, of organization, and of ideas. But the addition is a new world — a new and higher world, the world of a self-realizing thought, the world of an entelechy."⁶ "There are certainly different states of water, as ice and steam; but the relation of the solid to the liquid, or of either to the vapor, surely offers no analogy to the relation of protoplasm dead to protoplasm alive. That relation is not an analogy but an antithesis, the antithesis of antitheses. In it, in fact, we are in the presence of the one incommunicable gulf — the gulf of all gulfs — that gulf which Mr. Huxley's protoplasm is as powerless to efface as any other material expedient that has ever been suggested since the eyes of men first looked into it — the mighty gulf between death and life."⁷

"The differences alluded to (they are, in order, organization and life, the objective idea — design, and the subjective idea — thought), it may be remarked, are admitted by those very Germans to whom protoplasm, name and thing, is due. They, the most advanced and innovating of them, directly avow that there is present in the cell 'an architectonic principle that has not yet been detected.' In pronouncing protoplasm capable of active or vital movements, they do by that refer, they admit also, to an immaterial force, and they ascribe the processes exhibited by protoplasm — in so many words — not to the molecules, but to organization and life."⁸

"Was it molecular powers that invented a respiration — that perforated the posterior ear to give a balance of air; that compensated the fenestra ovalis by a fenestra rotunda; that placed in the auricular sacs those otolithes, those express stones for hearing? Such machinery! The chordæ tendineæ are, to the valves of the heart, exactly adjusted check-strings; and the contractile columnæ carneæ are set in, under contraction and expansion, to equalize their length to their office..... Are we to conceive such machinery, such apparatus, such contrivances, merely molecular? Are molecules adequate to such things — molecules in their blind passivity, and dead, dull, insensibility?.... Surely in the presence of these manifest ideas, it is impossible to attribute the single peculiar feature of protoplasm — its vitality, namely — to mere molecular chemistry. Protoplasm, it is true, breaks up into carbon, hydrogen, oxygen, and nitrogen, as water does into hydrogen and oxygen; but the watch breaks similarly up into mere brass, and steel, and glass. The loose materials of the watch — even its chemical material if you will — replace its weight, quite as accurately as the constituents, carbon, etc., replace the weight of the protoplasm. But neither these nor those replace the vanished idea, which was alone the important element."⁹ There is, therefore, something in protoplasm which cannot be weighed or otherwise measured, and to which the vital phenomena are to be referred.

If then the argument from analogy fails in its application to vital phenomena, there can be no pretence that it is valid in its application to the phenomena of mind. If we refuse to take the first step, even Professor Huxley cannot require us to take those which follow.

Besides the analogical argument, Materialists insist that there is direct evidence of the correlation of physical, with vital, and mental force. Let it be remembered what this means. Correlated forces are such as may be converted, the one into the other, and which are consequently in their nature identical. The thing, therefore, in this case, to be proved is that light, heat, etc., can be changed into life and thought, and that the latter are identical with the former, both classes being resolvable into motion of the molecules of matter.

The proof is substantially this. The animal body generates heat by the combustion of the carbon of the food which it receives, precisely as heat is produced by the combustion of carbon out of the body. And it has been experimentally proved that the quantity of heat produced in the body, is precisely the same due allowances being made, as the same amount of carbon would produce if burnt out of the body. Vital heat, therefore, is identical with physical heat.

Again, muscular force is produced precisely in the same way as physical force. The potential energy of the fuel moves the steam engine. Its work or power is measured and determined by the amount of power stored in the wood or coal consumed in its production. The source and measure of muscular power, are in like manner to be found in the food we eat. Its potential energy, derived from the sun as is the case with the potential energy of wood and coal, when liberated, produces its due amount, so much and no more, of muscular power. Muscular power, therefore, is as purely physical, produced in the same way, and measured by the same standard, as the power of the steam-engine.

In like manner, "nervous energy, or that form of force, which, on the one hand, stimulates a muscle to contract, and on the other, appears in forms called mental," is merely physical. It comes from the food we eat. It moves. The rate of its motion is determined to be ninety-seven feet in a second. Its effects are analogous to those of electricity. It is, therefore, for these and similar reasons, inferred that "nerve-force is a transmuted potential energy." This is no less true of nerve-force when manifested in the form of thought and feeling. Every external manifestation of thought-force, argues Professor Huxley, is a muscular one, and therefore analogous to other forces producing similar effects. Besides, it has been proved that every exercise of thought or feeling is attended by an evolution of heat, which shows that thought is resolved into heat. "Can we longer doubt, then, that the brain, too, is a machine for the conversion of energy? Can we longer refuse to believe that even thought is, in some mysterious way, correlated to the other natural forces? and this, even in face of the fact that it has never yet been measured?"¹⁰

To unscientific men of ordinary intelligence, to men not devoted to the study of the sensuous, it is a matter of astonishment that such arguments should be regarded as valid. Admitting all the above facts, what do they prove? Admitting that animal heat is the same in source and nature with heat outside the body; admitting that muscular power is physical in its nature and mode of production; admitting that nerve-force is also physical; what then? Do these facts give any solution of the mysteries of life, of organization, alimentation, or reproduction? Do they in any measure account for the formation of the eye or ear; for the mutual relations and interdependence of the organs of the body? Admitting these forces to be physical; who or what uses them? What guides their operation so as to answer a preconceived design? Admitting muscular power to be physical, what calls it into exercise at one time and not at another; beginning, continuing, or suspending it, at pleasure? It is plain that the facts adduced, are no solution either of vital or of voluntary phenomena. And when we come to thought, admitting that mental action is attended by a development of heat, does that prove that thought and heat are identical? When ashamed we blush, when afraid we become pale; do these facts prove that shame and fear and their bodily effects are one and the same thing? Does concomitancy prove identity? In proving the former, do you establish the latter? Do the facts adduced prove that shame is heat and heat shame, and that the one may be converted into the other? All the world knows that sorrow produces tears; but no one infers from this coincidence that sorrow and salt water are identical. Even Professor Tyndall, one of "the advanced thinkers," tells the Materialists, that when they have proved everything they claim to prove, they have proved nothing. They leave the connection between mind and body precisely where it was before.¹¹

Direct Arguments against the Theory of the Correlation of Physical, and Vital, and Mental Forces

1. They are heterogeneous. All physical forces are alike. They all tend to produce motion. They all tend to equilibrium. They are all measurable, by weight, or velocity, or by their sensible effects. They are all unintelligent. They act by necessity, without choice, without reference to an end. In all these respects mental forces are directly the reverse. They do not produce motion, they only guide and control it. They resist a state of equilibrium. They counteract physical force. As soon as vitality is gone, the chemical forces come into play and the plant or animal decays. They cannot be measured. Forces which do not admit of measurement, do not admit of correlation, for correlation involves sameness in quantity. "Thought," says President Barnard, "cannot be a physical force, because thought admits of no measure. I think it will be conceded without controversy that there is no form of material substance, and no known force of a physical nature (and there are no other forces), of which we cannot in some form definitely express the quantity, by reference to some conventional measuring unit.... No such means of measuring mental action has been suggested. No such means can be conceived..... Now, I maintain that a thing which is unsusceptible of measure cannot be a quantity; and that a thing that is not even a quantity, cannot be a force."¹²

Again, vital and mental force act with intelligence, with forethought, with freedom, and with design. Wherever the intelligence may reside, it is perfectly evident that all vital operations are carried on in execution of a purpose. Heat and electricity can no more fashion an eye than brass and steel can make a watch, or pen and paper write a book. Intelligent force, therefore, differs in kind from unintelligent force. They are not only different, but contradictory; the affirmation of the one is the negation of the other.

Prof. Joseph Henry, of the Smithsonian Institute, is admitted to be one of the most eminent naturalists of the age; distinguished not only for the thoroughness of his researches, but for soundness of judgment, and for the rare gift of being able to appreciate different kinds of evidence. He admits the correlation of physical forces, but protests against the obliteration of the distinction between them and vitality and mind. "The body," he says, "has been called 'the house we live in,' but it may be more truly denominated the machine we employ, which, furnished with power, and all the appliances for its use, enables us to execute the intentions of our intelligence, to gratify our moral natures, and to commune with our fellow beings. This view of the nature of the body is the furthest removed possible from Materialism; it requires a separate thinking principle. To illustrate this, let us suppose a locomotive engine equipped with steam, water, fuel, — in short, with the potential energy necessary to the exhibition of immense mechanical power; the whole remains in a state of dynamic equilibrium, without motion, or signs of life or intelligence. Let the engineer now open a valve which is so poised as to move with the slightest touch, and almost with a volition to let on the power to the piston; the machine now awakes, as it were, into life. It rushes forward with tremendous power; it stops instantly, it returns again, it may be, at the command of the master of the train; in short, it exhibits signs of life and intelligence. Its power is now controlled by mind — it has, as it were, a soul within it."¹³ This illustration holds just so far as it was intended to hold. The intellect which controls the engine is not in it, nor is it affected by its changes. Nevertheless, in the body, as well as in the engine, the controlling intellect is equally distinct from the physical force, which both so wonderfully exhibit.

In more direct reference to vitality, Professor Henry says: "Vitality gives startling evidence of the immediate presence of a direct, divine, and spiritual essence, operating with the ordinary forces of nature, but being in itself entirely distinct from them. This view of the subject is absolutely necessary in carrying out the mechanical theory of the equivalency of heat and the correlation of the ordinary physical forces. Among the latter vitality has no place, and knows no subjection to the laws by which they are governed."¹⁴

Dr. Beale¹⁵ is equally explicit. He constantly insists that what acts voluntarily, with choice to accomplish an end, cannot be physical; and that in vital and mental operations there is unquestionable evidence of such voluntary action. He says, "I regard 'vitality' as a power of a peculiar kind, exhibiting no analogy whatever to any known forces. It cannot be a property of matter, because it is in all respects essentially different in its actions from all acknowledged properties of matter. The vital property belongs to a different category altogether."¹⁶ He argues also to prove that organization cannot be referred to physical force. "It cannot be maintained that the atoms arrange themselves, and devise what positions each is to take up, — and it would be yet more extravagant to attribute to ordinary force or energy, atomic rule and directive agency. We might as well try to make ourselves believe that the laboratory fire made and lighted it self, that the chemical compounds put themselves into the crucible, and the solutions betook themselves to the beakers in the proper order, and in the exact proportions required to form certain definite compounds. But while all will agree that it is absurd to ignore the chemist in the laboratory, many insist upon ignoring the presence of anything representing the chemist in the living matter which they call the 'cell-laboratory.' In the one case the chemist works and guides, but in the other, it is maintained, the lifeless molecules of matter are themselves the active agents in developing vital phenomena.... No one has proved, and no one can prove, that mind and life are in any way related to chemistry and mechanics.... Neither can it be said that life works with physical and chemical forces, for there is no evidence that this is so. On the other hand it is quite certain that life overcomes, in some very remarkable and unknown manner, the influence of physical forces and chemical affinities."¹⁷ On a former page he had said, "In order to convince people that the actions of living beings are not due to any mysterious vitality or vital force or power, but are in fact physical and chemical in their nature, Professor Huxley gives to matter which is alive, to matter which is dead, and to matter which is completely changed by roasting or boiling, the very same name. The matter of sheep and mutton and man and lobster and egg is the same, and, according to Huxley, one may be transubstantiated into the other. But how? By 'subtle influences,' and 'under sundry circumstances,' answers this authority. And all these things alive, or dead, or roasted, he tells us are made of protoplasm, and this protoplasm is the physical basis of life, or the basis of physical life. But can this discoverer of 'subtle influences' afford to sneer at the fiction of vitality? By calling things which differ from one another in many qualities by the same name, Huxley seems to think he can annihilate distinctions, enforce identity, and sweep away the difficulties which have impeded the progress of previous philosophers in their search after unity. Plants, and worms, and men are all protoplasm, and protoplasm is albuminous matter, and albuminous matter consists of four elements, and these four elements possess certain properties, by which properties all differences between plants, and worms, and men, are to be accounted for. Although Huxley would probably admit that a worm was not a man, he would tell us that by 'subtle influences' the one thing might be easily converted into the other, and not by such nonsensical fictions as 'vitality,' which can neither be weighed, measured, nor conceived."¹⁸

In the latter portion of his book Dr. Beale shows that the brain is not a gland to secrete thought as the liver does bile; nor is thought a function of the brain, nor the result of mechanical or chemical action; nor is the brain a voltaic battery giving shocks of thought, as Stuart Mill conjectures; but it is the organ of the mind, not for generating, but for expressing thought.

To quote only one more authority, we refer to the eminent naturalist Wallace, the friend and associate of Darwin, and the zealous defender of his theory. "If," says he, "a material element, or a combination of a thousand material elements in a molecule, are alike unconscious, it is impossible for us to believe, that the more addition of one, two, or a thousand other material elements to form a more complex molecule, could in any way tend to produce a self-conscious existence. To say that mind is a product or function of protoplasm, or of its molecular changes, is to use words to which we can attach no clear conception. You cannot have, in the whole, what does not exist in any of the parts;.... either all matter is conscious, or consciousness is something distinct from matter; and in the latter case, its presence in material forms is a proof of the existence of conscious beings, outside of, and independent of, what we term matter."¹⁹

2. A second argument against the doctrine of the correlation of vital and physical forces is that in fact they are not convertible. Motion and heat are said to be correlated, because one can be changed into the other, measure for measure. But no one has ever changed death into life, dead matter into living matter. This Professor Huxley admits. If the simplest living cell once dies, all the science in the world cannot make it alive. What is dead can be made alive only by being taken up and assimilated by that which is still living. The life, therefore, is not due to the chemical properties of that which is dead. So far as chemistry is concerned, there is no known difference between protoplasm dead and protoplasm alive; and yet there is all the difference between them of life and death. That difference, therefore, is not chemical. Until scientific men can actually change heat and electricity into life, and go about raising the dead, men will be slow to believe that heat and life are identical; and until they can transmute physical force into intelligence and will, they cannot convert "thinkers" into Materialists.

3. Another argument against this theory is the inadequacy of the cause to the assumed effect. The doctrine is that the relation between correlated forces is quantitive; so much of the one will produce so much of the other. But we know that great mental agitation may be produced by the mere sight of certain objects, and that these mental states may call into action violent muscular force. According to the hypothesis, the impression on the nerves of sight or hearing is first transformed into mental force, and that again into muscular and molar energy. This, President Barnard, who presents this argument, pronounces to be absurd, "since it makes a small force equivalent to a large one."²⁰

President Barnard further argues against this theory from the fact that the mental states produced by impressions on the senses are, at least in many cases, obviously due not to the physical impression, but to the idea therewith connected. If you insult a Frenchman in English, it produces no effect; if the insult be expressed in his own language, it rouses him to fury. The meaning of the words is not a physical force, and yet it is to the meaning the effect is due. Dr. Barnard says, "when it is demanded of us to pronounce as physicists that spiritual existence is an absurdity and religion a dream, it seems to me that no choice is left us but to proclaim our dissent, or to be understood by our silence to accept the doctrine as our own. When such is the alternative, for one I feel bound to speak, and to declare my conviction that as physicists we have nothing to do with mental philosophy; and that in endeavouring to reduce the phenomena of mind under the laws of matter, we wander beyond our depth, we establish nothing certain, we bring ridicule upon the name of positive science, and achieve but a single undeniable result, that of unsettling in the minds of multitudes convictions which form the basis of their chief happiness."²¹

4. Physicists cannot carry out their own theory. Even those least susceptible of the force of the supersensuous, are compelled to admit that there is more in mental and vital action than blind physical force can account for. Dr. Carpenter, as we have seen, assumes the presence of "a directive agency;" the Germans of an "architectonic principle" unknown, and uncorrelated, in living matter, to explain undeniable facts for which physical force furnishes no solution. Others, whose spiritual nature is not so entirely subjected to the sensible, break down entirely. Thus Professor Barker, of Yale College, after devoting his whole lecture to prove that vital force and even thought "are correlated to other natural forces" (i.e., identical with them), comes at the end to ask: "Is it only this? Is there not behind this material substance, a higher than molecular power in the thoughts which are immortalized in the poetry of a Milton or a Shakespeare, the art creations of a Michael Angelo or a Titan, the harmonies of a Mozart or a Beethoven? Is there really no immortal portion separable from this brain-tissue, though yet mysteriously united to it? In a word, does this curiously fashioned body inclose a soul, God-given, and to God returning? Here science veils her face, and bows in reverence before the Almighty. We have passed the boundaries by which physical science is inclosed. No crucible, no subtle magnetic needle can answer now our questions. No word but His who formed us can break the awful silence. In the presence of such a revelation science is dumb, and faith comes in joyfully to accept that higher truth which can never be the object of physical demonstration."²²

It thus appears, after all, that there is in man a soul; that the soul is not the body, nor a function of it; that it is the subject and agent of our thoughts, feelings, and volitions. But this is precisely the thing which the lecture is devoted to disproving. Thus Professor Barker's science gives up the ghost at the feet of his religion. It quenches its torch in the fountain of an order of truths higher than those which admit of "physical demonstration." The proton pseudos of the whole theory is, that nothing is true which cannot be physically demonstrated; that is, which cannot be felt, weighed, or otherwise measured.