The great treasure-house of nature is open to all, and the      only fee demanded for inspection is attention.—Detrosibr.
Observation** of nature is the only source of truth. Discursive observation is the art of noticing circumstances evident to the senses. Men who do this intentionally and carefully, with a view of acquiring a knowledge of phenomena and their causes, are distinguished for their varied knowledge and often for their great discoveries. Shakspere must have owed the varied facts interwoven into his delineations of human character to this source. The clever personations of Garrick were suggested by his curious observations of men and manners. Sir Walter Scott is known to have been a careful observer. It is said, 'no expression escaped him if it bore on the illustration of character.'
     ** The term observation is used here in the sense in which
     it is commonly understood, signifying cognisance in general.
     It includes whatever information we acquire by the meant of
     consciousness, or experience, or through the agency of the
     senses.
Claude Lorraine, with a passionate sympathy for the beautiful, sate in the fields from sun-rise to dewy eve, watching, catching, and saturating his very soul, as it were, with all the evanescent beauties of a summer's day, as they chased each other over the face of the fair scene; fixing on canvass, taking captive and imprisoning in our cabinets, the wanton daughters of nature, that before his time never were caught, but flitted before the fascinated eye only long enough to make the heart afterwards feel more achingly the void of their vanishing. And the artist who has done all this, do we not justly call him an imaginative painter, to distinguish him from those meaner geniuses who were, in painting, very like Crabbe in poetry, merely faithful delineators of the vulgarer objects of social life, bunches of carrots, drunken boors, chamber maids and chimney corners.
'Has the reader ever seen Mr. Macready in the character of Macbeth? If he have, he can never forget the stupefied murderer withdrawing from the chamber in which he has just done the dread act, with fascinated gaze retreatingly regarding his royal victim, and awaking with a guilty start as he runs unconsciously against his hard-souled partner in guilt, who in vain tries to infuse into the weaker spirit of her paralysed husband her own metaphysical superiority. In this scene we know that Mr. Macready's acting was perfect, for the pressure at our heart, the suspension of our breathing, and the creeping of our hair, made us feel that it was so. We see him now, as stealthily he places his foot over the threshold of the chamber of death to re-appear on the stage; the intensely staring eye, that cannot remove from what 'tis horror to look upon; the awfully natural absorption of his soul by that "sorry sight," which one little minute has brought about; his starting and awaking from his entranced state, as he runs against his wife in his retreat, and his full passionate burst of blended remorse, terror, and superstition, as refusing counsel, regardless of remonstrance, heedless of probable detection, he pours forth his "brain-sickly" convictions, of having in one little moment cut the cable that had held him to the rest of the great human family. All this we can see in our mind's eye, for the actor gave us a picture of passion that time can never obliterate. But how would it have been with a cloddish unimaginative fellow, whom nature never intended should understand Shakspere? Would he not, conscious that he was among shoals and quicksands of feelings, too nice for his appreciation, seek to tear over all by a tempest of rant, which would be a more ruthless murder on Shakspere than Macbeth's on the king? And why should we be delighted with Mr. Macready's delineation, and disgusted with the ranter? Simply because the former has observed, treasured up, and felt every genuine exhibition of human feeling that came in his way, and applied it appropriately to all the situations to which it was related in nature. A single instance will make this clear. Mr. Kean one night, in the concluding part of the combat scene of Richard III., when supposed to be wounded to the death, before falling, steadily regarded his foe, and painfully raising his right arm in act to strike, the relaxed and dying limb, unable to second the spirit, fell heavily and harmlessly to his side, indicating merely the fierce bravery of the usurper living in all its strength, when the body which it would move, was all but a senseless clod. Pit, gallery, and boxes arose with an enthusiasm beyond description, and by their repeated plaudits bore testimony the intense naturalness of the struggle. The actor being afterwards complimented upon the hit, said, that he had taken the action from Jack Painter, the prize-fighter, when the latter was beaten in some one of his contests, and it immediately struck the tragedian that the very same thing would come in beautifully in the dying scene of Richard III. What was this, if not imagination? Kean saw Painter's action to be the natural effects of undying valour in vain endeavouring to contend against overwhelming power. Remembering and associating it with his previous conception of the character of Richard III., the actor saw it could be most strikingly incorporated with that picture of passion the usurper's death should present to our view. Seeing this, he combined it with his previous delineation, and thereby did precisely the same thing as the poet in using a fine simile, or the painter in introducing sun-light over a part of his picture. It was a portion of nature carried away by the actor to be reproduced on a future and fitting occasion.'*
The beginning of all knowledge is observation. It has been shown by Mr. Mill that 'axioms,' which lie at the foundation of all reasoning and all science, 'are experimental truths—generalisations from observation. The proposition that Two straight lines cannot inclose a space—or, in other words, Two straight lines which have once met do not meet again, but continue to diverge—is an induction from the evidence of our senses.'** 'Axioms are but a class of inductions from experience: the simplest and easiest cases of generalisation,' from the facts furnished to, us by our senses or by our internal consciousness.'***
Autobiography, or the metaphysical revelation of a man to himself, is a source of valuable psychological and moral truths. From this centre frequently radiate new lights upon human nature. But this is resolvable into a species of mental observation. It is self-inspection.
We have lately been told that 'Poetry is called upon to work in the discovery of truth. The imagination has always been the great discovering power. Discoveries are the poetry of science. The case is rare indeed in which, by merely advancing step by step in the exercise of the logical faculty, any new truth has been arrived at. Logic comes afterwards, to verify that which imagination sees with its far-darting glance.'****
     * Phrenology Tested, by A. M., of the Middle Temple, pp.
     143-5.
 
     ** Logic, vol 1, p. 305.
 
     *** Idem, pp. 328-9.
 
     **** W. J. Fox's Lectures to the Working Classes: Genius and
     Poetry of Campbell, p.;5.
This seems to call upon us to recognise the imagination as fresh source of truth. But the definition of imagination, as given by Emerson, reveals to us its origin in observation;—'The imagination may be defined to be the use which reason makes of the material world. Shakspere's imperial muse tosses the creation like a bauble from hand to hand, to embody any capricious shade of thought that is uppermost in his mind.' Hence, though we agree with Gilfillan that imagination is thought on fire, we must confess that the ignition is material.
We will, however, hear a poet's defence of his fraternity:—'Poets are vulgarly considered deficient in the reasoning faculty; whereas no man was ever a great poet without having it in excess, and after a century or two, men become convinced of it. They jump the middle terms of their syllogisms, it is true, and assume premises to which the world has not yet arrived; but time stamps their deductions as invincible.'*
Imagination is based on observation, and bears the same relation to the 'material world' that the magician bears to the appliances of his art. Imagination is the dexterous and astonishing use of realities. It is a species of mental experiment, whereby, without permission of the line-and-rule men, we join strange things together, and to the surprise of every body, the junction is a happy one. 'Angelo's greatness lay in searching for untried existence.'** But observation primarily suggests the combination. If, as in the case of Angelo, imagination essays the highest flights of genius, and goes in search of untried existence, it is not existence out of nature, but founded upon nature—its success is a revelation of some hidden reality.
     * Lowell's Conversations on the Old Poets.
 
     ** J. T. Seymour; Oracle of Reason.
Some of the most praised conceptions of Shakspere have been traced by critics to the tritest observation. Instance Hamlet's remark:—
     There's a divinity doth shape our ends,
     Bough-hew them as we will.
Critics tell us, that Shakspere here fell into the conventional cant of a mechanic making skewers. But it is no detraction to cull the best phrases from the most common sources. Knight remarks:—'Philosophy, as profound as it is beautiful! says the uninitiated reader of Shakspere. But he that is endued with the wisdom of the commentators, will learn how easy it is to mistake for philosophy and poetry what really only proceeded from the very vulgar recollection of an ignorant mind. Dr. Farmer informs me, says Steevens, that these words are merely technical. A woodman, butcher, and dealer in skewers, lately observed to him, that his nephew (an idle lad), could only assist in making them; he could rough-hew them, but I was obliged to shape their ends. To shape the ends of wood skewers, i. e., to point them, requires a degree of skill: any one can rough-hew them. Whoever recollects the profession of Shakspere's father, will admit that his son might be no stranger to such terms. I have frequently seen packages of wool pinned up with skewers.'* To admit the likelihood of all this, notwithstanding Mr. Knight's jeer at the 'wisdom of the commentators,' is rather to exalt than degrade the genius of Shakspere, who could derive exalted figures from humble sources. The 'Athen?um,' far more wisely than Mr. Knight, in this instance, observes:—'This is the test of a truly great man; that his thoughts should be things, and become things in instantaneous act, and not for a moment mere speculations and abstractions.'
As the theories of the schoolmen subside, and men no longer ignore nature, it will become recognised as the source rather than the tool of intellect. We shall have less occasion to contend that all lofty and sublime ideas derive their value and beauty from their coherence with the instincts of sensation, 'Poetry, we grant, creates a world of its own; but it creates it out of existing materials.' 'Imagination' may be but 'thought on fire,' but the spark, which ignites it, is material. Is there any other distinction between the nights of the rhapsodist and those of genius, than that genius illumines reality and rhapsody obscures it? 'We know of no great generalisation that has ever been made by a man unacquainted with the details on which it rests.'
Experiment is invented observation. It is putting into operation certain supposed causes in order to observe their effects. An experiment may be defined as an observation, which we are at some trouble to make. Experiment is usually set down as being a process of discovering truth different from observation. It is evidently included under observation, and there is no practical advantage in separating it. Discursive, general, ordinary, or common observation is the observation of the phenomena we find. Experiment is observation of the phenomena we bring together. Experimental observation has been the great agent of modern discovery. Newton ranked it as the most valuable knowledge. Whatever is not founded on phenomena is hypothesis, and has no place in experimental philosophy. It is the principal source of accurate facts. When Jenner first communicated to John Hunter, what he thought respecting the prevention of small pox—'Don't think, but try; be patient, be accurate,' was Hunter's characteristic reply. Locke remarks—'While the philosophy of Aristotle prevailed in the schools, which dealt often in words without meaning, the knowledge of nature was at a stand; men argued concerning things of which they had no idea; in this enlightened age, we keep to trial and experiment, as the only certain foundation of philosophy.'
     * Philosophy and Religion of Shakspere, pp. 173-4
 
     **  No 946. p. 1103.
 
     *** Athen?um, No. 946, p. 1191.
Hypothesis may be noticed here as being a species of embryo experiment. Hypothesis is guessing at the truth. It is a conjecture or supposition relating to the cause of an effect. It imagines that where certain conditions exist, the desired result will ensue. But all these conjectures must be founded on observation. For, in the wildest conjecture, unless made by a madman, there is some reason. Hypothesis is incipient truth founded on a few facts which make it probable, but not on sufficient to make it certain. Hypothesis does not directly discover truth, but it is a guide to experiment, which does. The hypotheses of Columbus respecting an unknown continent, did not of itself discover America—but it directed the experiment of his voyage there, which did. To hypothesise alone is the error of the visionary and the dreamer. Practical wisdom, as far as possible, tests hypothesis by experiment. Sir C. Bell conjectured that the nervous fluid of the human body was analogous to galvanic fluid, and then, by experiments on various animals, he endeavoured to test his hypothesis. However, great thinkers arise who are best employed in contriving plans for others to execute—in telling others what they are to do. Great poets belong to this class. They are often incapable of the concentrated labour of furnishing proofs of their hypothesis. Gladly should we recognise the mission of such men. They work for humanity by thinking for humanity. 'All who think,' says Lytton, 'are co-operative with all who work.' Labour supplies our wants, thought teaches us dominion over nature. Labour is but the means of subsistence, it is thought that makes it the source of wealth by multiplying its powers.
To the value of hypothesis Mr. Mill bears this testimony, that by suggesting observations and experiments, it puts us upon the road to, independent evidence, if it be really attainable, and till it be attained, the hypothesis ought not to count for more than a suspicion. The function of hypothesis is one which must be reckoned absolutely indispensable in science. Without such assumption, science would not have attained its present state. Nearly everything which is now theory was once hypothesis.*
     * Logic, Vol. II, p. 18.
Induction is systematic observation of a given class of phenomena. It consists in bringing together a variety of facts and instances, carefully and patiently viewing them in all possible lights to discover from a comparison of the whole what, if any, new principle is elicitable. Induction is an experiment with a number of facts, to see if any general result can be arrived at. Thus observation is of three kinds—discursive, experimental, and inductive. For brevity of speech, we use respectively the terms observation, experiment, and induction, as the names of the three recognised modes of investigation. But it facilitates a clear view of this subject, to note that experiment and induction are but phases of observation—and that observation is the great source of the discovery of truth.
Discursive observation and experiment are the sources of facts or particular truths. Nature, poetically says Dr. Reid, is put to the question by a thousand observations and experiments, and forced to confess her secrets. Out of these secrets induction gathers its general truths, which become the premises of argument. Facts, like stones, are of little service while scattered—it is in the edifice raised by them that their value is apparent. They have been compared to blocks, upon one of which, if a person stand, he has but a partially increased view; but when many are piled up, a person from their summit commands the prospect round. Particular truth seldom proves anything but itself. Argument is proving something else, and we have seen that that which is proved must be contained in something which proves it. In other words, an argument is an assertion or denial of something substantiated by other things—by facts.
Gall observed the peculiar formation of a certain head, but the one fact proved nothing, except that the head had a certain form. It was a barren observation, except that it suggested to his imagination the hypothesis that the peculiar form of the head might be caused by peculiarity of mind. This set him upon the experiment of observing the habits and dispositions of the individual in order to test his hypothesis. But the one fact of finding a peculiarity proved nothing new of any value. The two facts, though incident, were hardly convincing. They proved only that a peculiar head was accompanied in one case by peculiar habits—but whether one was the cause of the other, or whether the phenomena were in any way connected, still remained unknown. When, however, Gall, Spurzheim, and others, had travelled through Europe, making observations and experiments, and at last putting all the facts and instances together, and carefully and patiently viewing them in all possible lights, and finding that they shadowed forth that the brain was the organ, the map and measure of intelligence, they inducted a general truth, which enters the lists of argument and takes its place as an addition to our metaphysical and moral treasures.
Mr. Macaulay, who, perhaps, might be accused of underrating both Bacon and Induction, with a view of exalting Aristotle, remarks that 'The vulgar notion about Bacon we take to be this, that he invented a new method of arriving at truth, which method is called induction, and that he detected some fallacy in the syllogistic reasoning which had been in vogue before his time. This notion is about as well founded as that of the people who, in the middle ages, imagined that Virgil was a great conjurer. Many who are far too well informed to talk such extravagant nonsense, entertain what we think incorrect notions as to what Bacon really effected in this matter. The inductive method has been practised ever since the beginning of the world by every human being. It is constantly practised by the most ignorant clown, by the most thoughtless schoolboy, by the very child at the breast. That method leads the clown to the conclusion, that if he sows barley he shall not reap wheat. By that method, the schoolboy learns that a cloudy day is the best for catching trout. The very infant we imagine is led by induction to expect milk from his mother or nurse, and none from his father. Not only is it not true that Bacon invented the inductive method, but it is not true that he was the first person who correctly analysed that method and explained its uses. Aristotle had long before pointed out the absurdity of supposing that syllogistic reasoning could ever conduct men to the discovery of any new principle, had shown that such discoveries must be made by induction and by induction alone, and had given the history of the inductive process concisely, indeed, but with great perspicuity and precision. We are not inclined to ascribe much practical value to that analysis of the Inductive method which Bacon has given in the second book of the Novum Organon. It is, indeed, an elaborate and correct analysis. But it is an analysis of that which we are all doing from morning to night, and which we continue to do even in our dream.'*
     * Macaulay's Hist Essays, vol. 3, p. 407.
It is not 'some fallacy in the syllogistic reasoning' which Bacon is supposed to have detected, it is rather the partial protection against error afforded by syllogisms, which he exposed and provided against, for which he is estimated. Certainly Aristotle must have had a very different opinion of the value of inductive philosophy from that entertained by Bacon, or he would have indoctrinated his disciples with it. Few will doubt that had Bacon's Novum Organon appeared in the place of Aristotle's logic, and Aristotle's work in the place of Bacon's, that the advancement of learning in the world would now be in a very different state. Could Bacon have arrested the attention of the ancient sages with his methods of discovering new principles, ancient philosophy, instead of being a treadmill, would have been a path, and we should not have had a contempt for all learning which was useful. When Posidonius said that we owed to philosophy the principles of the arch and the introduction of metals. We should not have had Seneca repudiating such insulting compliments, nor Archimedes considering that geometry was degraded by being employed in anything useful.
But these observations of Macaulay have the merit of showing us that induction has its foundation in nature, and afford a further confirmation of our views, that observation is the source of our knowledge, and that it is the province of logic to teach us to systematise our thoughts. Observation, experiment, hypothesis and induction, are but different names for the operation—varying in degree, in method, in expedient, and elaboration—whereby we discover truth. Nature is the treasure-house of truth, and the sole fee of appropriation is attention.
Much discussion has taken place upon the nature of necessary truths. Mr. Mill, however, after an elaborate analysis of Dr. Whewell's theory, pronounces that 'nothing is necessary except the connection between a conclusion and the premises.' A necessary truth is commonly defined as a proposition, the negation of which is not only false, but inconceivable. Mr. Mill contests this doctrine in words embodying suggestions of great value.
'Now I cannot but wonder that so much stress should be laid upon the circumstance of inconceivableness, when there is such ample experience to show that our capacity or incapacity of conceiving a thing has very little to do with a possibility of the thing in itself; but is in truth very much an affair of accident, and depends upon the past history and habits of our own minds. There is no more generally acknowledged fact in human nature, than the extreme difficulty at first felt in conceiving anything as possible, which is in contradiction to long established and familiar experience; or even to old and familiar habits of thought. And this difficulty is a necessary result of the fundamental laws of the human mind. When we have often seen and thought of two things together, and have never in any one instance either seen or thought of them separately, there is by the primary law of association an increasing difficulty, which in the end becomes insuperable, of conceiving the two things apart. This is most of all conspicuous in uneducated persons, who are in general utterly unable to separate any two ideas which have once become firmly associated in their minds; and if persons of cultivated intellect have any advantage on the point, it is only because, having seen and heard and read more, and been more accustomed to exercise their imagination, they have experienced their sensations and thoughts in more varied combinations, and have been prevented from forming these inseparable associations. But this advantage has necessarily its limits. The man of the most practised intellect is not exempt from the universal laws of our conceptive faculty. If daily habit presents to him for a long period two facts in combination, and if he is not led during that period either by accident or intention to think of them apart, he will in time become incapable of doing so even by the strongest effort; and the supposition that the two facts can be separated in nature, will at last present itself to his mind with all the characters of an inconceivable phenomenon. There are remarkable instances of this in the history of science: instances, in which the wisest men rejected as impossible, because inconceivable, things which their posterity, by earlier practice and longer perseverance in the attempt, found it quite easy to conceive, and which everybody knows to be true. 'If, then, it be so natural to the human mind, even in its highest state of culture, to be incapable of conceiving, and on that ground to believe impossible, what is afterwards not only found to be conceivable but proved to be true; what wonder if in cases where the association is still older, more confirmed, and more familiar, and in which nothing ever occurs to shake our conviction, or even suggest to us any conception at variance with the association, the acquired incapacity should continue, and be mistaken for a natural incapacity? It is true our experience of the varieties in nature enables us, within certain limits, to conceive other varieties analogous to them. We can conceive the sun or moon falling; for although we never saw them fall, nor ever perhaps, imagined them falling, we have seen so many other things fall, that we have innumerable familiar analogies to assist the conception; which after all, we should probably have some difficulty in framing, were we not well accustomed to see the sun and moon move, (or appear to move,) so that we are only called upon to conceive a slight change in the direction of motion, a circumstance familiar to our experience. But when experience affords no model on which to shape the new conception, how is it possible for us to form it? How, for example, can we imagine an end to space or time? We never saw any object without something beyond it, nor experienced any feeling without something following it. When, therefore, we attempt to conceive the last point of space, we have the idea irresistibly raised of other points beyond it. When we try to imagine the last instant of time, we cannot help conceiving another instant after it Nor is there any necessity to assume, as is done by a modern school of metaphysicians, a peculiar fundamental law of the mind to account for the feeling of infinity inherent in our conceptions of space and time; that apparent infinity is sufficiently accounted for by simpler and universally acknowledged laws.'*
     * Mill's Logic, vol. 1, pp. 313-17.
Thus we stand on the verge of boundless possibility. What truths may yet be discovered in that great and untrodden field, which lies without our experience, no man can tell. All we have yet brought between assertion and proof, is all we have yet conquered, is all that we as yet know, is all that we can yet rely upon. The search after the untried is the highest and apparently the inherent aspiration of roan. The revelation of new worlds continually rewards his noble ambition. At once arrested and allured by the magnificence of nature—we wonder, we work, we wait.