Lessons from nature, as manifested in mind and matter

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EXTRACT FROM RULES.

Preface

Observation and experience have convinced me of the narrowing and misleading effects upon the mind of an incomplete conception of what is meant by the term "Nature."

It is too generally taken as denoting the assemblage of phenomena external to and apart from the human mind, which none the less is one of the most important objects which presents itself to our perception. Hence arises a necessary imperfection. But a worse evil follows. " Nature," taken in this limited sense, is often made use of to explain that which has been tacitly excluded from it. Thus it is that the facts and processes of Eeason are apt to be first ignored in order that they may be afterwards treated as if the mere phenomena of irrational nature were sufficient to explain them.

Impressed with this conviction it has been my endeavour to point out in the following chapters (in however imperfect and fragmentary a manner) what I deem the most important lessons to be derived from " Nature," in the broad sense of that word as a great whole of which the mind of man forms part. For us indeed the facts of mind form the inevitable starting-point from which we must set out in order to study,

Vin PKEFACE.

logically, the phenomena of irrational nature, and to investigate, if we may, their cause and purpose. There is no doubt, in thus proceeding, a danger of Anthropomorphism — of attributing to the First Cause merely human characteristics, and projecting as it were our personality, as in the Brocken shadow, far beyond its proper limits ; but the danger of Antanthropomorphism is at present much greater — the danger, that is, of allowing the facts of reason to be obscured and overshadowed by an analogously enlarged distortion of the world of sense, which ever so clamorously reiterates its claims on our attention and regard.

The following chapters are mainly reprints from articles which have from time to time appeared in the ' Quarterly,' * Dublin/ ' Contemporary,' and ' Fortnightly ' Reviews between June 1871 and November 1875. These various articles, however, were originally written with the intention that they should be augmented, re-arranged and republished in an assemblage of consecutive chapters as they now appear.

ANALYTICAL TABLE OF CONTENTS.

CHAPTER I. THE STARTING-rOINT

" Our own continued existence is a primary truth known to us with supreme certainty, and this certainty cannot be denied without involving the destruction of all knowledge whatever."

Reasons why the contemplation of nature has become a passion — Speculative activity of our age — Our need of a starting-point which cannot he gainsaid — The study of mind an experimental science — The two dangers of popular discussions — Authority has no place in philosophy — Doubt only to be cured by investigation — Bewildering effect of the present conflict of opinion — Expediency of stimulating a thorough inquiry — The Agnostic philosophy — Every philosophy of nescience stultifies itself — Yet is to be directly encountered — On condition of admitting three preliminary propositions — The first proposition — The second proposition — The third proposition — The teaching of a leading Agnostic as to our knowledge of our own existence— His analysis incomplete — His system can be destroyed by his own weapons — As considered in its parts — And considered as a whole— Self-existence known primarily — Self-existence implied in " certainty " itself — The refutation of nescience not to be evaded on the ground of the inadequacy of language — A further consequence— What the word " thought " implies — What truth is — " Necessary " truth — The Agnostics' assertion, if valid, implies many truths they deny — Logical consequences — What is implied in asserting the trustworthiness of memory — A curious fallacy — Mr. Spencer's view as to our knowledge of our own existence — He asserts a truism or an absurdity — An illustration — An argumentum ad horninem — What he asserts implies the existence of what he denies — Conclusion arrived at — The first lesson from nature PP» 1 — 28

X ANALYTICAL TABLE OF CONTENTS.

Chapter II. First Truths

" Knowledge must be based on the study of mental facts, and on undemonstrable truths which declare their own absolute certainty, and arc seen by the mind to be positively and necessarily true."

Self-knowledge shows we can have absolute certainty without proof — Reasons why we should begin with a study of mind before studying external nature — And endeavour to harmonize our thoughts and feelings — Some differences between these — Thought, not feeling, the test ot truth — Balmes and Mr. Herbert Spencer as to the necessity of starting wilh undemonstrable truths — Mr. Spencer's test of ultimate truths, false because merely negative — Two distinct classes of unimaginable propositions — A fallacy of Professor Helmholtz — Mr. Spencer's example of absolute inconceivability — Our perception of necessary truth not limited by experience — Propositions positively seen to be necessarily true — Summary of the propositions here arrived at — Mr. Bain's ultimate criterion of truth — The principle of contradiction denied by Mr. SpeDcer, and the highest faculties of the human mind ignored — As also by Mr. Lewes — The validity of our reasoning faculty — Mr. Lewes confounds reasoning with sensible association — Summary and conclusion.

Chapter III. The External World

"The real existence of an external world made up of objects possessing qualities such as our faculties declare to us they do possess, cannot be logically denied and may rationally be affirmed."

A justification of our belief in the external world here logically required — Prevalent scepticism on this subject amongst modern philosophers, and its cause — Mr. John Stuart Mill — Mr. Spencer's Transfigured Eealism — His justification of it— Outcome of it — His reply to criticism — Its insufficiency — His proof-case as to sound — The truth of his affirmation*; denied — Mr. Spencer's reply to the charge of fundamental incoherence — Rejoinder to such reply — Need of a more detailed survey of his positions — His observations on the relativity of our feelings — The impossibility of logically denying the objective validity of our perceptions as to even the secondary qualities of objects — Mr. Spencer on the relativity of our relations between feelings — On the effects of structure,

ANALYTICAL TABLE OF CONTENTS. x.i

age, and state on relations of sequence — On the relation between our perception of sequence, co-existence and difference, and their sensible accompaniments — Mr. Spencer's view as to nervous relations — As to the reality of an ontological order and nexus — Mr. Spencer's confusion of the intellect with the sensible occasions of its activity — Mr. Lewes's position — Agrees with Mr. Spencer fundamentally — Recapitulation — Conclusion, that we may securely repose on the declarations of our . senses as to the existence and properties of external objects pp. 55 — 81

CHAPTEE IV.

LANGUAGE.

" Rational language is a bond of connexion between the mental and materia, worlds which is absolutely peculiar to man."

Language the bond between mind and matter — Language emotional and rational — Rational language mental and bodily — Different categories of language — External expression a necessary accompaniment of rational animality — Prevalent confusion on the subject — Deaf mutes — Mr. Tylor on savages — Sir John Lubbock — Conclusion . . pp. 82 — 94

Chapter V. Duty And Pleasure

" Perceptions of right and wrong, and of our power of choice, and consequent responsibility, are universally diffused amongst mankind, and constitute an absolute character separating man from all other animals."

The existence of moral conceptions a fact of nature — Are such conceptions universal amongst mankind ? — A definition of morality — The distinctness of the conception generally admitted — Needful cautions — Examples of morality in savages — Mr. Tylor and Sir John Lubbock — Do moral judgments contradict one another? — The popular modern school implicitly denies morality — Mr. John Stuart Mill's self-contradiction in this matter — The origin of the conception "right" — Materially and formally moral acts — Mr. Darwin's view — That moral perceptions are simply the more enduring instincts — Mr. Darwin's instances — Mr. Huxley's reply to Mr. Darwin's critics — Free-will — Mr. Herbert Spencer's views— Conclusion pp. 95 — 127 xn ANALYTICAL TABLE OF CONTENTS.

Chapter VI. Man

u The study of religious beliefs, of progress, or degradation, and of the community of nature found in the most diverse races of men, show (together with language and moral perception) that man differs fundamentally from brutes, while the anatomical resemblances to animals which his frame exhibits in no way invalidate the argument drawn from the study of mind, that his origin (like his nature) is peculiar and distinct."

Other human characteristics to be studied besides language and moral perception — Special call now for this study — Two conflicting hypotheses — Test questions for these — Three new subjects of inquiry — Preliminary note — First new subject, religion — Prejudices — Mistakes — Savage faiths — Australians — Are the rudest religious ideas fundamentally like higher ones ? — Sacrifice — Second new subject, progress — Mr. Mott's remarks — Mr. Herbert Spencer's — Mr. Darwin's — Degradation certain — Adam — His descendants — Bude people may be moral — Third new subject, community of nature — Conclusions — Man's body — His embryonic development — Superficiality of Mr. Darwin's remarks on these subjects — Necessary physical conditions of animal rationality, as to structure — Man's resemblance to apes — As to development — Bearing of these matters on man's origin — Mistakes as to reversion — Other mistakes — Mr. Darwin's remarks as to insects — Man forms a kingdom by himself — Unity of human races — What shall be the verdict as to man's origin ? — Mr. Wallace's view T s — Free-will — Conclusion pp. 128—191

Chapter VII. The Brute

" The highest psychical powers of animals resemble the lower psychical faculties of man. The brute is devoid of reason, and instinct is a peculiar function of the material organism, automatic and blind."

Necessity of some recapitulation — Instinct, mode of studying it — The mode in use generally defective — Keason for this — Kesults of introspection — Organic and intellectual memory — List of the mind's higher powers — Which are common to all mankind — Danger of a special fallacy — Instinct cannot perform rational acts — But can do what reason cannot do — Mr. Herbert Spencer's admissions — Mr. Darwin's anecdotes— As to brute rationality — Parity of psychical nature between veiy different animals — Professor Huxley on animal rationality — Mr. Lewes's admissions — John Miiller — Man's lower psychical faculties — List of them — Their relation jto the psychical faculties of brutes — The development of the individual

ANALYTICAL TABLE OF CONTENTS. Xiil

— Human automatism — Curious views as to the nature of instinct — What is instinct? — What it is — Unity of each organism — Definition of instinct — Energy of matter — A new energy in man — Ground's of this decision — Stupidity of animals — Conclusion . . pp. 192 — 243

Chapter VIII. Likenesses IX Animals* And Plants

" The facts of mimicry and of the various kinds of homology as exhibited in comparative anatomy, teratology and pathology, reveal an internal force and dynamic agency, the soul, in each animal, which forms one indissoluble unity with its material frame."

Two kinds of likeness to be considered — Mimicry — Not to be explained by accidental variations — This shown by plants — Second order of likenesses — The number of these perceived varies with the direction of our attention — Natural classification — Of parts and organs — Philosophical anatomists — The vertebral theory of the skull — Analogous and homologous parts — Likenesses not due to inheritance — Mr. Spencer's explanations — Independent similarities — Homoplasts and homoplasy — Catalogue of homologies — Not due to the survival of the fittest — Evidences from comparative anatomy — From teratology — From pathology — Teleology — A resurrection — Development — Are there cranial vertebras? — Amphioxus — The answer — A deeper question — Homology reveals internal forces— Or " soul " in each animal — Mr. Lewes — Conclusion . pp. 244 — 279

Chapter IX. Natural Selection

•* The hypothesis of natural selection originally put forward as the origin of species, has been really abandoned by Mr. Darwin himselfj and is untenable. It is a misleading positive term denoting negative effects, and, as made use of by those who would attribute to it the origin of Man, is an irrational conception/'

Futility of attempts to ignore internal forces — Origin of species, the author's view — Mr. Darwin's original view — His later views — And admitted errors — Consequent need of careful criticism — Professor Huxley's defence — Points contended for by the author — Differ from Mr. Darwin's view — What is and is not implied in man's animality — Mr. Wallace's claims to originality — Mr. Francis Galton's view — Mr. Darwin's style — He begs the question he argues — Conclusion as to " natural selection."

xiv ANALYTICAL TABLE OF CONTENTS.

Chapter X. Sexual Selection

" Sexual selection is an hypothesis which neither has been nor can be proved true, but the falsehood of which is demonstrated by a mass of zoological data.-' ,

Sexual selection, an accessory hypothesis — Has been made to include two distinct things — Marked characters certainly arise independently of it —Insects — Fishes and reptiles — Beasts — Birds — Voice — Mr. Wallace opposes Mr. Darwin — His hypothesis as to colour — Mr. Darwin opposes Mr. Wallace's hypothesis — Need of an internal force — Its sufficiency — Mr. Darwin influenced, by a priori views — An illustration — Uncertainties of the hypothesis — Sexual selection and man — Mr. Darwin's style — Ancillary hypotheses needed — Conclusion as to sexual selection.

CHAPTER XL

AN EriSODE.

" Mr. Chauncey Wright's criticism of the author's views having been republished and widely circulated by Mr. Darwin, the reply to that criticism is here reproduced."

A digression induced by special circumstances — May be passed over without detriment to the general argument — Mr. Chauncey Wright's criticism — Mainly addressed to two points — The first of these — Sudden adaptive modifications — Improper interpretations — Mr. Wright's second point — Design and accident — Innate force — The inductive philosophy — Mr. Wright on intellectual genius — The giraffe's neck — An advantage possessed by Mr. Darwin's theory which does not properly belong to it — Critical details — An objection singular in a mathematician — An illustration in the growth of a tree — Vital forces — Verbal criticisms — Conclusion.

Chapter XII. Causes

"Truths vouched for by the intellect as positively necessary truths, compel our acceptance of a First Cause with power, knowledge, wisdom and goodness, and therefore prove the existence of final causes also — the existence of a personal God being the ultimate lesson taught by Nature, that as to its own cause."

The axiom of causation — Science points to no beginning — But either to a Pantheistic first cause — Or one distinct from the universe — Together with final causation — Thus supplying a key to evolution — Mr. Spencer's evolutionary formula — "Purpose " as shown in Nature— Formal law of

ANALYTICAL TABLE OF CONTENTS. xv

evolution — Non-theistic views — Mr. Spencer's — Professor Huxley's — The unknowable — Five objections to theism — First objection, prodigality of Nature — An old answer — Second objection — Third objection, pain and death — Sufferings of brutes — Apparently unworthy phenomena — Fourth objection, evolution negatives creation — Fifth objection, anthropomorphism — Conclusion ...... pp. 356 — 376

Chapter XIII. Consequences

"The consequences which flow from the acceptance or rejection of the teaching here advocated are and must be irtost momentous both to individuals and the community. Those who reject it are logically driven into extreme and irrational negation. Its bearing upon conduct is direct, and must necessarily powerfully affect the future through popular education. Such consequences may rationally serve to reinforce conclusions before arrived at on other grounds."

Various consequences, speculative and practical — Consequences of controversies before noticed — As to the Ego — As to the will — As to God — The immortality of the soul — Two phraseologies — Peculiar nature of man's soul — Consequences of rejecting Theism — Professor Tyndall's teaching — Mr. Spencer's teaching — Professor Huxley's teaching— Other declarations — General result — Intolerance of modern infidels — Atheism inconsistent with toleration — Practical consequences — Is truth necessarily desirable ? — Some propositions with ethical applications — Purity of intention — Sexual relations — Conduct in public men less influential than teaching — An objection to legal restrictions on marriage — Consequences as regards popular education — The Eev. William Mackintosh — A positive compromise — Need of a belief in future rewards and punishments — Two ambiguities — Education should stimulate the highest powers — Motives which move men to act — M. Le Play — Kesponsibility of public teachers — Characters of the Agnostic philosophy — Dislike of religion sometimes induces the acceptance of that philosophy — Conclusion, pp. 377 — 421

CIIAPTEE XIV.

A POSTSCRIPT.

" This postscript is called for by an unamended republication by Professor Huxley of his criticism on the * Genesis of Species,' of which he in part misapprehends, in part misrepresents the arguments. A Theist should anticipate a revelation. The Christian revelation asserts creation, but at the same time lays down principles which so harmonize with Evolution that no contradiction cac arise in this respect between its doctrines and physical science. This harmony must be preordained."

This postscript specially called for — Reason expects revelation — Modern philosophy has diverged from this attitude — Mr. Spencer and evolution — Evolution welcomed by Antichristians — Eational attitude of a Theist

XVI ANALYTICAL TABLE OF CONTENTS.

towards religious systems — Christianity asserts creation — The Genesis of Species — And Professor Huxley — A misapprehension — His astonishment — Another misapprehension — An explanation — Suarez — The fact of creation — Another misapprehension — Want of acquaintance with theology — Authorities — An utter mistake — Solvitur ambulando — Christianity and reason — Mode of controversy — Restatement of issue— A retrospect and conclusion pp. 422 — 449

Index , p. 451

LESSONS FROM NATURE.

Chapter I. The Starting-point

" Our own continued existence is a primary truth naturally made known to us with supreme certainty, and this certainty cannot bo denied without involving the destruction of all knowledge whatever. ,,

The philosophic contemplation of nature may be said to be a passion of the age in which we live. Nor is Reasons why the reason why, far to seek. Every physical science, pMioS^? 1 " when once its study is fairly begun, never fails S^omea* 8 to excite much interest, and in our day a certain pa8S10n - knowledge of physical science has become widely diffused. Most popular sciences, zoology, botany, and geology, &c, can be followed with ease by all commonly gifted minds, and the beauty, variety, and inexhaustible multitude of the facts and relations they disclose are such as may well make that interest become intense and absorbing. But when it is recollected that to the attraction these sciences possess in themselves there is now added the interest called forth by the generally diffused belief (whether rightly or wrongly entertained) that by these much light may be thrown upon the deepest problems and the most important questions which can occupy men's minds, it becomes easy to understand why a very large part of our popular lectures and of our periodical literature should be devoted to subjects of natural history, so treated as to bear, directly or by implication,

2 LESSONS FROM NATUEE. [Chap. I.

upon questions of origin and agency and purpose ; devoted, in short, to physical philosophy. The problem of the true relation subsisting between irrational and rational nature is the problem of the day. An endeavour then will here be made to elucidate what are the lessons taught us by a combined study of nature in its two aspects, rational and irrational.

It is probable that the last quarter of a century has, in speculative England, seen a more quickly growing and more our age. wide-spread crop of speculative questioning than any former period of like duration. More than this, it is doubtful whether any period of the world's past history has witnessed a more general uncertainty, not only respecting the solution of particular problems, but as to the possibility of satisfactorily and certainly answering any one of them.

Thus it has come about that from increased speculative activity, and the inability of physical science to satisfy the questions raised, men devoted to physical science have been forced into philosophy. " Metaphysics," which had become (especially in this country) a byword of reproach, are again avowedly pursued. A reaction has set in, and the importance of philosophy, indeed its absolute necessity as a basis for science, is made manifest by the most popular teachers of physical knowledge. On the Continent, Buchner, Vogt, Hartmann, and Strauss have powerfully aided in directing popular attention to philosophical problems. In England, in spite of the oft-repeated assertions of the unprogressiveness of metaphysics, and the comparisons drawn between the efforts of metaphysicians and those of Sisyphus, our bookshelves teem with evidence that devotion to philosophy is on the increase amongst us, and physicists such as Carpenter, Bence Jones, Bastian, Huxley, Tyndall, Darwin, Wallace, with many more, have all, in various degrees, wandered beyond the domain which is specially their own into the metaphysical region. Even that annual national congress, which was instituted expressly for the promotion of physical science, had its session of 1872 inaugurated by an address on " the mental processes by which are formed those fundamental

Chap. I.] THE STARTING^¥0INT; 3

conceptions of matter and force, of cause and effect, of law and order, which form the basis of all reasoning ;'" while, at Belfast, in 1874 it was opened by what may be fitly termed a sermon advocating the deliberate substitution of a religion of emotion for one of reason. Professor Huxley, some years ago,* bore witness to the needfulness of attending " to those philosophical questions which underlie all physical science ; " and he has again and again availed himself of his well-earned popularity to press upon his hearers metaphysical considerations, and to endeavour to make plain to them that the questions of really supreme importance are such as are philosophical.

In entering upon an inquiry which professes, as does this, to take nothing for granted unnecessarily our need of a

. i ... , nil starting-

or without criticism, we must be careful that our point which

cannot be

starting-point, in- our investigation of nature, shall gainsaid. be thoroughly satisfactory — containing truth which is absolutely unquestionable. Such a starting-point is supplied us by our passing mental states — the facts of consciousness itself. It is conceivable that the whole external world, and all existences external to ourselves, might be delusions, but everybody can see that while we actually have a feeling we must have it, and that no supernatural being could cause us to be thinking that which we at the same time do not think, or not to think anything while we are actually continuing to think it. Here, then, in consciousness itself we have a perfectly satisfactory starting-point, a firm rock which may serve as the corner-stone of a future edifice. Such an edifice we may find it possible to raise by inquiring into the activity of our own mind, by finding what it declares to be ultimate and certain truths (if it declares any to be such), by criticising the tests given as to such truths being certain and ultimate, and by examining the grounds on which we are, if at all, to accept such declarations as true, having, at the same time, seen what truth itself really is.

* Contemporary Review/ November 1871, pp. 443, 444.

4 LESSONS FKOM NATUKE. [Chap. I.

This task may appear a difficult and tedious one, but after The study of all it is one which comes strictly within the field of ^rhLentoT the experimental sciences, and is actually the most science. ce rtain science of them all. Its inductions repose upon the most direct of observations, and its deductions are tested by experiments of the most decisive kind. Whether "metaphysics" be or be not a cloud-land, this particular inquiry is at least to be made on firm ground, under a clear sky, and in bright sunlight. Before, however, entering upon the first inquiry, a preliminary caution may not be out of place. A widely extended discussion of philosophical ques- Thetwodan- tions such as that which now obtains is manifestly ETdiwus? 11 " open to two dangers, the one, a " hasty dogmatism," sions. ^ e qj^qy^ an a irrational scepticism." It is common

enough to find writers (such, e.g., as Professor Clifford) speaking in so dogmatic a tone that the unwary are in danger of mistaking confident assertion for proof, while the many, ever prone jurare in verba rnagistri, are but too apt to adopt themselves the dogmatic style merely on the authority of their chosen masters. For such, a judicious scepticism is the necessary remedy.

More common, however, is the danger of " irrational scepticism." And here a word of explanation may be addressed to those who may be offended by this phrase, fancying (in spite of the concluding phrase of the last paragraph) that I may deem "scepticism" to be generally "irrational." But it is manifest that in philosophy, reason, and reason only, Authority * s an d mus * ^e ^e su P reme an( l ultimate arbiter. in a pMoC ce ^ or ft ll those who are convinced that truth is phy - necessarily good, it is even wrong to accept any-

thing whatever as true which has not been made evident to the intellect. For such, no authority, however venerable, no consequences, however calamitous, as long as they do not in-

, , volve a contradiction, can or ought to stand in the

Doubt only to 9 D

i£v < StT i a by wa y °^ P^ ess l°gi c m following out to their final tion. results the processes of reason. As a consequence,

when* any man has become a victim to doubt, he has no

Chap. I.J THE STABTING-POINT. 5

rational choice, as he has no duty, but to reason out his doubts to the end: to seek to escape them by diverting his attention, or to obscure them by calling up a cloud of emotion, is not only useless but blameworthy. As it is for an individual so is it for a people. And if, as in England in the present day, we see a generation restlessly seeking on all sides, in a night of doubt, for the first glimmerings of a coming dawn, surely hearty sympathy and ready aid are called for in favour of men who show by such restlessness and questioning how they are seeking to gain a knowledge of truth which was at least never lost through any act or deed of theirs.

Now at the present time Englishmen are again and again called upon to treat as open questions the very first Bewildering principles of all reasoning, fundamental truths upon present conwhich the whole fabric of science reposes. And as opinion. but a small minority of the lecture-hearing, magazine-reading public can be supposed to have seriously taken up the study of philosophy, it follows that a certain number will fail to distinguish accurately between a healthy and an unhealthy scepticism. Not being accustomed to sound the depths of their own minds, and puzzled by the paradoxes of the sophists who now and again address them, some lose their hold upon all certainty and fall into a state of general doubt which is so undefined that it does not formulate itself in distinct propositions. Hence we too often encounter a vague and hazy scepticism, producing a languid and otiose state of mind which is, indeed, a symptom of incipient intellectual paralysis.

But since our object is to seek for certain positive truth, and to build up logically on such certain basis, it is Expediency needful to rouse attention, as far as may be, to this Inga^oenfeebling disease — a mental falling-sickness. In quiry. the presence of this evil it is surely well to try and drive such loiterers along the philosophic road, and to force on them an earnest and resolute questioning of themselves, so that they may know clearly that they do know what they know, and that they may not be persuaded unawares

6 LESSONS FEOM NATURE. [Chap. I.

out of their rational birthright. It is, of course, important that men should not be permitted to build upon a fancied knowledge which has not enough solidity to sustain the philosophical edifice; but it is certainly no less important that men should not be led to follow unsuspectingly an ignis fatuus till it plunges them into a quagmire of " universal doubt." To exaggerate our powers is dangerous, but to be possessed by a feeling of our utter impotence is fatal.

Now there is a school of philosophy (by courtesy so called) The Agnostic of considerable popularity, which is called by its philosophy. pp 0nen t g the " philosophy of nescience " — a name, however, which its supporters would hardly disclaim. They would hardly disclaim it because some of them willingly style themselves "Agnostics," or "know-nothings ;" meaning thereby that they know and can know nothing but appearances, and that nothing whatever can be really and absolutely known. Yet, very irrationally these know-nothings or Agnostics at the same time very confidently affirm that they, by their ignorance, absolutely and infallibly know that the healthy common sense of mankind has gone all wrong, and, what is more extraordinary still, that the greatest philosophers have perversely joined in accepting the common-sense delusions of the vulgar, and gone wrong too. Such philosophers have, indeed, agreed with the rest of mankind in affirming the certainty of their own continued existence and that of their fellow-men, together with an external world, the shape, number, and extent of the parts of which they declare they can really and absolutely know, in so far as such parts can be brought under the observation of their senses.