filled up which should be capable of to consider the five classes in their being supplied in a valid argument, order.

it would either stand thus, (forming a fallacy of one class,) or thus, (a fallacy of another ;) or at furthest we may say, that the conclusion is most likely to have originated in a fallacy FALLACIES OF SIMPLE INSPECTION, OR

of such and such a class. Thus in the illustration just quoted, the error committed may be traced with most probability to a Fallacy of Generalisation; that of mistaking an uncertain mark, or piece of evidence, for a certain one; concluding from an effect to some one of its possible causes, when there are others which would have been equally capable of producing it.

Yet, though the five classes run into each other, and a particular error often seems to be arbitrarily assigned to one of them rather than to any of the rest, there is considerable use in so distinguishing them. We shall find it convenient to set apart, as Fallacies of Confusion, those of which confusion is the most obvious characteristic; in which no other cause can be assigned for the mistake committed than neglect or inability to state the question properly, and to apprehend the evidence with definiteness and precision. In the remaining four classes I shall place not only the cases in which the evidence is clearly seen to be what it is, and yet a wrong conclusion drawn from it, but also those in which, although there be confusion, the confusion is not the sole cause of the error, but there is some shadow of a ground for it in the nature of the evidence itself. And in distributing these cases of partial confusion among the four classes, I shall, when there can be any hesitation as to the precise seat of the fallacy, suppose it to be in that part of the process in which, from the nature of the case and the tendencies of the human mind, an error would in the particular circumstances be the most probable.

CHAPTER III.

A PRIORI FALLACIES.

§ 1. THE tribe of errors of which we are to treat in the first instance are those in which no actual inference takes place at all: the proposition (it cannot in such cases be called a conclusion) being embraced, not as proved, but as requiring no proof; as a self-evident proof; or else as having such intrinsic verisimilitude, that external evidence not in itself amounting to proof is sufficient in aid of the antecedent presumption.

An attempt to treat this subject comprehensively would be a transgression of the bounds prescribed to this work, since it would necessitate the inquiry which, more than any other, is the grand question of what is called metaphysics, viz. What are the propositions which may reasonably be received without proof? That there must be some such propositions all are agreed, since there cannot be an infinite series of proof, a chain suspended from nothing. But to determine what these propositions are is the opus magnum of the more recondite mental philosophy. Two principal divisions of opinion on the subject have divided the schools of philosophy from its first dawn. The one recognises no ultimate premises but the facts of our subjective consciousness; our sensations, emotions, intellectual states of mind, and volitions. These, and whatever by strict rules of induction can be derived from these, it is possible, according to this theory, for us to know; of all else we must remain in ignorance. The opposite school hold that there are other existences, suggested indeed to our minds by these subjective phenomena, but not inferrible from them by any proAfter these observations we shall cess either of deduction or of inducproceed, without further preamble, | tion; which, however, we must, by

the constitution of our mental nature, | customed to call ideas of the mind. recognise as realities; and realities, When they themselves say that they too, of a higher order than the pheno- perceive the things by an immediate mena of our consciousness, being the act of a faculty given for that purefficient causes and necessary sub- pose by their Creator, it would be strata of all Phenomena. Among said of them by their opponents that these entities they reckon Substances, they find an idea or conception in whether matter or spirit; from the their own minds, and from the idea dust under our feet to the soul, and or conception infer the existence of from that to Deity. All these, ac- a corresponding objective reality. cording to them, are preternatural or Nor would this be an unfair statesupernatural beings, having no like- ment, but a mere version into other ness in experience, though experience words of the account given by many is entirely a manifestation of their of themselves; and one to which the agency. Their existence, together more clear-sighted of them might, and with more or less of the laws to generally do, without hesitation subwhich they conform in their opera- scribe. Since, therefore, in the cases tions, are, on this theory, apprehended which lay the strongest claims to be and recognised as real by the mind examples of knowledge à priori, the itself intuitively: experience (whether mind proceeds from the idea of a in the form of sensation or of mental thing to the reality of the thing itself, feeling) having no other part in the we cannot be surprised by finding matter than as affording facts which that illicit assumptions à priori conare consistent with these necessary sist in doing the same thing erronepostulates of reason, and which are ex- ously in mistaking subjective facts plained and accounted for by them. for objective, laws of the percipient mind for laws of the perceived object, properties of the ideas or conceptions for properties of the things conceived.

As it is foreign to the purpose of the present treatise to decide between these conflicting theories, we are precluded from inquiring into the exist- Accordingly, a large proportion of ence, or defining the extent and limits, the erroneous thinking which exists of knowledge à priori, and from char- in the world proceeds on a tacit asacterising the kind of correct assump-sumption that the same order must tion which the fallacy of incorrect obtain among the objects in nature assumption, now under consideration, which obtains among our ideas of simulates. Yet, since it is allowed them. That if we always think of on both sides that such assumptions are often made improperly, we may find it practicable, without entering into the ultimate metaphysical grounds of the discussion, to state some speculative propositions, and suggest some practical cautions, respecting the forms in which such unwarranted assumptions are most likely to be made.

§ 2. In the cases in which, according to the thinkers of the ontological school, the mind apprehends, by intuition, things, and the laws of things, not cognisable by our sensitive faculty, those intuitive, or supposed intuitive, perceptions are undistinguishable from what the opposite school are ac

two things together, the two things must always exist together; that if one thing makes us think of another as preceding or following it, that other must precede it or follow it in actual fact. And, conversely, that when we cannot conceive two things together, they cannot exist together, and that their combination may, without further evidence, be rejected from the list of possible occurrences.

Few persons, I am inclined to think, have reflected on the great extent to which this fallacy has prevailed, and prevails, in the actual beliefs and actions of mankind. For a first illustration of it, we may refer to a large class of popular superstitions. If any

story of Cæsar's accidentally stumbling in the act of landing on the African coast, and the presence of mind with which he converted the direful presage into a favourable one by exclaiming, "Africa, I embrace thee." Such omens, it is true, were often conceived as warnings of the future, given by a friendly or a hostile deity; but this very superstition grew out of a pre-existing tendency : the god was supposed to send, as an indication of what was to come, some. thing which people were already dis

in the case of lucky or unlucky names. Herodotus tells us how the Greeks, on the way to Mycale, were encouraged in their enterprise by the arrival of a deputation from Samos, one of the members of which was named Hegesistratus, the leader of armies.

one will examine in what circum- | agreeable circumstance was, indestances most of those things agree pendently of superstition, too insigwhich in different ages and by dif-nificant to depress the spirits by any ferent portions of the human race influence of its own. All know the have been considered as omens or prognostics of some interesting event, whether calamitous or fortunate, they will be found very generally characterised by this peculiarity, that they cause the mind to think of that of which they are therefore supposed to forbode the actual occurrence. "Talk of the devil and he will appear," has passed into a proverb. Talk of the devil, that is, raise the idea, and the reality will follow. In times when the appearance of that personage in a visible form was thought to be no unfrequent occurrence, it has doubt-posed to consider in that light. So less often happened to persons of vivid imagination and susceptible nerves that talking of the devil has caused them to fancy they saw him; as, even in our more incredulous days, listening to ghost stories predisposes us to see ghosts; and thus, as a prop to the à priori fallacy, there might Cases may be pointed out in which come to be added an auxiliary fallacy something which could have no real of mal-observation, with one of false effect but to make persons think of generalisation grounded on it. Fal- misfortune was regarded not merely lacies of different orders often herd as a prognostic, but as something or cluster together in this fashion, approaching to an actual cause of it. one smoothing the way for another. The evnoue of the Greeks, and favete But the origin of the superstition is linguis or bona verba quæso of the evidently that which we have as- Romans, evince the care with which signed. In like manner it has been they endeavoured to repress the utteruniversally considered unlucky to ance of any word expressive or sugspeak of misfortune. The day on gestive of ill-fortune; not from notions which any calamity happened has of delicate politeness, to which their been considered an unfortunate day, general mode of conduct and feeling and there has been a feeling every- had very little reference, but from where, and in some nations a reli- bona fide alarm lest the event so suggious obligation, against transacting gested to the imagination should in any important business on that day; fact occur. Some vestige of a similar for on such a day our thoughts are superstition has been known to exist likely to be of misfortune. For a among uneducated persons even in similar reason any untoward occur- our own day it is thought an unrence in commencing an undertak-christian thing to talk of or suppose ing has been considered ominous of the death of any person while he is failure, and often, doubtless, has really alive. It is known how careful the contributed to it, by putting the per- Romans were to avoid, by an indirect sons engaged in the enterprise more mode of speech, the utterance of any or less out of spirits: but the belief word directly expressive of death or has equally prevailed where the dis-other calamity: how instead of mor

From a similar feeling, "every substance," says Dr. Paris,* "whose origin is involved in mystery, has at different times been eagerly applied to the purposes of medicine. Not long since, one of those showers which are now known to consist of the excrements of insects fell in the north of Italy; the inhabitants regarded it as manna, or some supernatural pana

tuus est they said vixit; and "be the event fortunate or otherwise," instead of adverse. The name Maleventum, of which Salmasius so sagaciously detected the Thessalian origin (Maλoes, Maλoévros,) they changed into the highly propitious denomination Beneventum; Egesta into Segesta; and Epidamnus, a name so interesting in its associations to the reader of Thucydides, they exchanged for Dyrrhacea, and they swallowed it with such chium, to escape the perils of a word avidity, that it was only by extreme suggestive of damnum or detriment. address that a small quantity was "If an hare cross the highway," obtained for a chemical examination." says Sir Thomas Browne,* "there are The superstition, in this instance, few above threescore that are not though doubtless partly of a religious perplexed thereat; which notwith-character, probably in part also arose standing is but an augurial terror, from the prejudice that a wonderful according to that received expres- thing must of course have wonderful sion, Inauspicatum dat iter oblatus properties. lepus. And the ground of the conceit was probably no greater than this, § 3. The instances of à priori falthat a fearful animal passing by us lacy which we have hitherto cited portended unto us something to be belong to the class of vulgar errors, feared; as upon the like considera- and do not now, nor in any but a tion the meeting of a fox presaged rude age ever could, impose upon some future imposture." Such super-minds of any considerable attainstitions as these last must be the ments. But those to which we are result of study; they are too recon-about to proceed have been, and still dite for natural or spontaneous growth. are, all but universally prevalent But when the attempt was once made to construct a science of predictions, any association, though ever so faint or remote, by which an object could be connected, in however far fetched a manner, with ideas either of pros-hibits itself in many of the most acperity or of danger and misfortune, was enough to determine its being classed among good or evil omens.

An example of rather a different kind from any of these, but falling under the same principle, is the famous attempt, on which so much labour and ingenuity were expended by the alchemists, to make gold potable. The motive to this was a conceit that potable gold could be no other than the universal medicine: and why gold? Because it was so precious. It must have all marvellous properties as a physical substance, because the mind was already accustomed to marvel at it.

* Vulgar Errors, book v. chap. 21.

among thinkers. The same disposition to give objectivity to a law of the mind-to suppose that what is true of our ideas of things must be true of the things themselves-ex

credited modes of philosophical investigation, both on physical and on metaphysical subjects. In one of its most undisguised manifestations it embodies itself in two maxims, which lay claim to axiomatic truth: Things which we cannot think of together cannot co-exist; and Things which we cannot help thinking of together must co-exist. I am not sure that the maxims were ever expressed in these precise words, but the history both of philosophy and of popular opinions abounds with exemplifications of both forms of the doctrine.

To begin with the latter of them : * Pharmacologia, Historical Introduction, p. 16.

cially of the bad metaphysics, which the human mind has never ceased to produce. Our general ideas contain nothing but what has been put into them, either by our passive experience, or by our active habits of thought; and the metaphysicians in all ages, who have attempted to construct the laws of the universe by reasoning from our supposed necessities of thought, have always proceeded, and only could proceed, by laboriously finding in their own minds what they themselves had

Things which we cannot think of ex- | the philosophy not only of Descartes, cept together, must exist together. but of all the thinkers who received This is assumed in the generally re- their impulse mainly from him; in ceived and accredited mode of reason- particular the two most remarkable ing which concludes that A must ac- among them, Spinoza and Leibnitz, company B in point of fact, because from whom the modern German meta"it is involved in the idea." Such physical philosophy is essentially an thinkers do not reflect that the idea, emanation. I am indeed disposed to being a result of abstraction, ought to think that the fallacy now under conconform to the facts, and cannot make sideration has been the cause of twothe facts conform to it. The argu-thirds of the bad philosophy, and espe ment is at most admissible as an appeal to authority; a surmise, that what is now part of the idea must, before it became so, have been found by previous inquirers in the facts. Nevertheless, the philosopher who more than all others made professions of rejecting authority, Descartes, constructed his system on this very basis. His favourite device for arriving at the truth, even in regard to outward things, was by looking into his own mind for it. "Credidi me," says his celebrated maxim, "pro regulâ gene-formerly put there, and evolving from rali sumere posse, omne id quod valdè dilucidè et distinctè concipiebam, verum esse; whatever can be very clearly conceived must certainly exist; that is, as he afterwards explains it, if the idea includes existence. And on this ground he infers that geometrical figures really exist, because they can be distinctly conceived. Whenever existence is "involved in an idea," a thing conformable to the idea must really exist; which is as much as to say, whatever the idea contains must have its equivalent in the thing; and what we are not able to leave out of the idea cannot be absent from the reality.* This assumption pervades

*The author of one of the Bridgewater Treatises has fallen, as it seems to me, into a similar fallacy when, after arguing in rather a curious way to prove that matter may exist without any of the known properties of matter, and may therefore be changeable, he concludes that it cannot be eternal, because "eternal (passive) existence necessarily involves incapability of change." I believe it would be difficult to point out any other connection between the facts of eternity and unchangeableness than a strong association between the two ideas. Most of the à priori arguments,

their ideas of things what they had first involved in those ideas. In this way all deeply-rooted opinions and feelings are enabled to create apparent demonstrations of their truth and reasonableness, as it were out of their own substance.

The other form of the fallacyThings which we cannot think of together cannot exist together, --including, as one of its branches, that what we cannot think of as existing cannot exist at all,-may thus be briefly expressed: Whatever is inconceivable must be false.

Against this prevalent doctrine I have sufficiently argued in a former Book,* and nothing is required in this place but examples. It was long held that Antipodes were impossible because of the difficulty which was found in conceiving persons with their heads in the same direction as our feet. And

both religious and anti-religious, on the origin of things, are fallacies drawn from the same source.

* Supra, book ii. chap. v. § 6, and ch. vii. § 1, 2, 3, 4. See also Examination of Sir William Hamilton's Philosophy, chap. vi. and elsewhere.