system. The ego itself has been reduced by various modes to inanition and intellectual extinction; and whereas nothing seems at first sight more axiomatic and final than the primary truths of arithmetic and geometry, yet thinkers of all ages have not only speculated eagerly on the whence and the why of such truths, but have even taxed their imaginations to the extent of conceiving worlds in which 2 + 2 might make 5. If these well-known facts are insufficient to prove the inherent Skepticism of the speculative intellect, this can only be attributed to the very self-same tendency, and is, in truth, a strong confirmation of its existence. 2. But if the human intellect in presence of truths generally supposed to be indubitable and compulsory, reveals a Skeptical bias, we find precisely the same disposition manifested in its mode of dealing with problems confessedly insoluble. Its unwillingness or inability to concede an absolute negation is just as strong as its indisposition or powerlessness to grant an unconditional affirmation. Among the numerous questions which have engaged the attention of the human mind, there are many which are not only, on account of our present imperfect knowledge, incapable of receiving even an approximate solution, but of which we are unable to conceive, with every allowance for the attainments of the future, the bare possibility of their ever receiving such a solution. Let us take as an instance the origin of the universe. I must confess myself quite unable to conceive, even hypothetically, a theory on the subject of so simple and undoubted a character, as to exclude all further speculation and inquiry. And yet upon this inscrutable matter a countless variety of theories have been propounded, from the mythological fables of remote antiquity to the nebular hypothesis of our own day. And, probably, unless the nature of the human intellect changes considerably from what it is at present, there never will come a time when speculation on such an abstruse subject will finally cease, from the recognition of the patent fact, that anything approaching a complete solution of the problem is a self-evident impossibility.2 These words were written some years ago, but no one acquainted with the most recent results of astronomical research, will require to be told that the nebular hypothesis has now received its quietus, leaving apparently no theory to occupy its place. At present, so far as Physicists are concerned, the Universe is an orphan. 2 'Cependant c'est une des principales et des plus ordinaires maladies de l'homme d'estre travaillé d'une curiosité inquiète pour des choses qu'il ne peut sçavoir, et qu'il lui est vraisemblement plus avantageux d'ignorer que d'en prendre connoissance, puisque Dieu a limité la sphère d'activité de son âme, qui ne peut pas pénétrer jusques-là.' La-Mothe-le-Vayer, Soliloques Scept., Ed. Liseux, p. 2. Or take another question-the exact mode in which our sensations are formed. It is hardly too much to say that from the very nature of the case an adequate explanation of this mysterious fact is simply inconceivable. The requisite and only possible conditions of successful investigation are manifestly unattainable. Nor can I conceive any advance in the sciences of Physiology and Psychology sufficiently great as to remove this inherent impossibility. And yet there is scarce any subject-matter of human inquiry which has received so much attention from psychologists on the one hand and physiologists on the other. Indeed, most of this labour has been expended without any great prospect of a satisfactory result, so far as definite knowledge is concerned, perhaps without even expecting the final solution of so profound an enigma. In a word, the mental energies of men in these and in the numberless other cases which might have been adduced, seem to me like a wild beast perpetually measuring with restless paces the extreme limits of the cage from which it has nevertheless long since ascertained there can be no escape; or like a watchful army surrounding a fortress which it cannot but admit to be impregnable, it is yet continually belying its admission by its conduct, for it is always on the look-out for some unguarded corner or weak position by which an entry may haply be effected. It should, however, be remembered as some set-off against such hopeless enterprises and unrealised desires, that these ceaseless attempts to accomplish impossibilities are not only the intellectual instincts of our race, but are incidentally productive of good results. Weaker fortresses, themselves once deemed impregnable, have been forced to succumb in some degree to such unsleeping vigilance. Besides, soldiers ever on the alert attain a continual increase of efficiency, and if, notwithstanding all their efforts, they fail to achieve what is impossible, they must admit, if they can, such failure to be nothing less than inevitable. A further cause for the inability of our faculties to attain complete demonstration is to be found in the individual and isolated character of every perception or idea we possess. Each act of sensation or reflection is a single independent fact of consciousness, having its own individual colouring, characteristics, and extent. So that not only are our faculties limited in respect of their own inherent powers, but they are further limited as regards their participation in any common stock of universal Truth. The individual differences which characterise our powers of perceiving and of thinking were known to and acknowledged by the philosophers of Greece many centuries ago. It formed, indeed, a part of the creed of every eminent Greek thinker from the time of Protagoras and his aphorism, Man is the measure of all things,' to the final elaboration of the doctrine in the schools of the later Skeptics. Nor were they backward in applying such a cogent argument to refute dogmatic conclusions and general systems of belief, which were avowedly based on the common consent of humanity. Within a recent date this individuality of sense-perceptions, or 'personal equation,' as it has been called, has been recognised by scientists of our own day, and has become in certain astronomical experiments a necessary part of the calculations pertaining to them. But in point of fact this 'personal equation' is true not only of the modus operandi of the senses, but of all the definitions and determinations of the intellect-the nature and extent of every idea, the quality and scope of every imagination, the meaning attached to words and propositions; in a word, to every part and outcome of the apparatus which man employs as a reasoning being. Hence each individual has his own private mirror, in which is reflected each part and parcel of his knowledge. And when we bring all these reflections together in order to establish, as we think, universal and impregnable truth, we cannot be surprised if the whole should present the appearance of a piece of glass cut into numberless facets, and that any object reflected by it should be diverse and multitudinous rather than uniform and identical. Nor would the behaviour of the human intellect be, I conceive, greatly altered were its limitations to some extent removed, and its present faculties immeasurably increased both in number and efficiency. If, e.g., like Voltaire's Micromegas, we were gifted with a thousand senses instead of five, our fate would probably still be that so plaintively described by the inhabitant of Sirius: ‘Il nous reste encore je ne sais quel désir vague, je ne sais quelle inquiétude, qui nous avertit sans cesse que nous sommes peu de chose, et qu'il y a des êtres beaucoup plus parfaits.' Nay, we have good warrant for assuming that such an enlargement in the number and scope of our faculties would only produce a corresponding increase in the number of questions to be solved and, ipso facto, of difficulties in their solution. Hence the possessor of five senses, if a skeptic, would, were his senses increased to a thousand, probably become in direct arithmetical ratio two hundred times more skeptical than before. Let us suppose for a moment that we were endowed with some such enormous increase in the number, 1 Micromegas, Hist. philosophique, chap. ii. variety, and power of our senses and mental faculties as that suggested by Voltaire; that we were able, for instance, to comprehend by methods now inconceivable the real causes and modes of working of all the great physical forces by which we are surrounded; that we could perceive the molecular changes that take place in electricity and magnetism as readily as we can see the movement of our own limbs; that we could hear the sap percolating through the cells and capillary tubes of all kinds of vegetation, from the tiniest herb to the loftiest tree, as easily as we can hear the rush of water through a drain-pipe; that we could see and number the vibrations of light or sound-waves as readily as we can reckon our paces; that we could feel the changes in our brain-substance which are said to be the invariable antecedents of all our different states of consciousness as quickly and keenly as we feel the pain of a blow; that, lastly, we could trace those subtle links which form our mental associations with no more difficulty than we can number the links of a chain we hold in our hands, and that all dialectical processes were as vividly presented to our inner senses as the most crude, mechanical operation might be to our bodily senses, and the inevitable result of such a stupendous addition to our faculties and modes of knowledge would be a proportionate increase in our bewilderment, and an enlarged scope for curiosity and incredulity. So that the truth of the Hebrew Skeptic's maxim is amply attested by the whole history of Skepticism, He that increaseth knowledge increaseth sorrow,' or as Shelley in his magnificent play has expressed the same sentiment, by making the furies reproach Prometheus: Dost thou boast the clear knowledge thou waken'dst for man? These perishing waters; a thirst of fierce fever, Hope, love, doubt, desire, which consume him for ever. Instead, then, of supposing that an extension of our present powers would operate as an antidote to Skepticism, we must, I suspect, proceed in the very opposite direction. What is needed is not the extension, but the still further limitation of our reasoning faculties. We with our five senses, elaborated and enhanced by the gifts of reason and imagination, are in point of fact only too well equipped to find perfect satisfaction in the result of our investigations. It is a melancholy instance of the mixed nature of our divinest gifts that the very faculty by which we reason is that which enables and incites us to doubt, that the means we adopt in order to construct is like a builder's scaffolding, equally available for purposes of destruction, and that those nations and individuals are freest from Skepticism which are closest akin to brutes and idiots. Hence we may term doubt the Nemesis of faith, the inevitably reactionary consequence of dogmatism. It presupposes reasoning and intelligence, it postulates systematised beliefs, convictions which have attained a greater or less degree of coherence and stability. It is therefore the outcome, not of ignorance, but of culture; the characteristic, not of the childhood, but of the mature age of mankind. No traces of Skepticism appear in Greek or Hindoo philosophy until long after the formation and establishment of numerous systems of belief and speculation, and in most languages of uncultured nations there is no word for doubt. III. Another cause of Skepticism may be found in the necessary relations between human reason and its creature and instrument, human language. This is, of course, a very large subject, and I cannot do more than point out a few instances in which the unavoidable uncertainty pertaining to the use of language seems to be a prolific source of Skepticism. 1. Let us first glance at the mode by which we acquire knowledge. We shall find, I think, that it affords a proof both of the necessity and uncertainty of human language. To the child or uneducated adult the object of an act of perception is indistinguishable from the perception itself. The tree, e.g. which is seen, is the same object as the image of it imprinted on the retina or retained in the memory; and this confusion is shown in the language employed, which for the most part makes no distinction between the outward object and its ideal representation, calling both by a common name. But no sooner is this unavoidable conjunction of the real and ideal analysed, than it is seen that a discrepancy may and often must exist between the actual object and its mental representation. The senses, e.g. cannot always be depended upon for giving a perfectly accurate account of the phenomena submitted to them, and therefore the terminology which assumes and seeks to express such accuracy must be faulty and unreliable. Hence the continual mistakes made by the senses in the judgments of perception may be said to constitute the first chapter in every systematic treatise on Skepticism. Nor is it easy to see how with the possession of senses of much greater accuracy, or of a language in which all mental abstractions were duly differentiated and distinguished from real objects, the danger of some such confusion could be altogether averted. Moreover, a man's language, with all its immense variety of |