V 



SCIENCE. 



3 



8. Place the instrument with the needles approximately 

 perpendicular to the magnetic meridian, turning it so as 

 to bring b and P to the south of the vertical plane bisect- 

 ing the small angle between the projections of r b, r 1 b ] 

 and r, and r 1 to the north side of it. 



9. By aid of the micrometer screw bring the luminous 

 image to its middle position on the scale. 



10. Cause R B, B 1 R 1 to have different temperatures. 

 The luminous image is seen to move in such a direction 

 as is due to r approaching the cooler, and receding from 

 the warmer of the two deflectors B R, B 1 R'. — Proceed- 

 ings Royal Society, Edinburgh. 



{Continued from page 270.] 

 THE UNITY OF NATURE. 

 By the Duke of Argyll. 

 IV. 



ON THE LIMITS OF HUMAN KNOWLEDGE CONSIDERED WITH 

 REFERENCE TO THE UNITY OF NATURE. 



And yet, although it is to Nature in this highest and 

 widest sense that we belong — although it is out of this 

 fountain that we have come, and it is out of its fullness that 

 we have received all that we have and are, men have 

 doubted, and will doubt again, whether we can be sure of 

 anything concerning it. 



If this terrible misgiving had affected individual minds 

 alone in moments of weariness and despair, there would 

 have been little to say about it. Such moments may come 

 to all of us, and the distrust which they leave behind them 

 may be the sorest of human trials. It is no unusual result 

 of abortive yet natural effort and of innate yet baffled curi- 

 osity. But this doubt, which is really nothing more than a 

 morbid effect of weakness and fatigue, has been embr.iced 

 as a doctrine and systematized into a philosophy. Nor can 

 it be denied that there are some partial aspects of our 

 knowledge in which its very elements seem to dissolve and 

 disappear under the power of self-analysis, so that the sum 

 of it is reduced to little more than a consciousness of ignor- 

 ance. All that we know of Matter is so different from all 

 that we are conscious of in Mind, that the relations be- 

 tween the two are really incomprehensible and inconceiv- 

 able to us. Hence this relation constitutes a region of 

 darkness in which it is easy to lose ourselves in an abyss of 

 utter skepticism. What proof have we — it has been often 

 asked — that the mental impressions we derive from objects 

 are in any way like the truth? We know only the phen- 

 omena, not the reality of things. We are conversant with 

 things as they appear, not with things as they are " in them- 

 selves." What proof have we that these phenomena give 

 us any real knowledge of the truth? How, indeed, is it 

 possible that knowledge so "relative" and so "condi- 

 tioned " — relative to a mind so limited, and conditioned by 

 senses which tell us of nothing but sensations — how can 

 such knowledge be accepted as substantial? Is it not 

 plain that our conceptions of Creation and of a Creator are 

 all mere "anthropomorphism?" Is it not our own shadow 

 that we are always chasing ? Is it not a mere bigger image 

 of ourselves to which we are always bowing down ? 



It is upon suggestions such as these that the Agnostic 

 philosophy, or the philosophy of Nescience, is founded — 

 the doctrine that, concerning all the highest problems 

 which it both interests and concerns us most to know, we 

 never can have any knowledge or any rational and assured 

 belief. 



It may be well to come to tlie consideration of this doc- 

 trine along those avenues of approach which start from 

 the conception we have now gained of the unity of Nature. 



Nothing, certainly, in the human mind is more wonder- 

 ful than this — that it is conscious of its own limitations. 

 Such consciousness would be impossible if these limita- 

 tions were in their nature absolute. The bars which we 

 feel so much, and against which we so often beat in vain, 

 are bars which could not be felt at all unless there were 

 something in us which seeks a wider scope. It is as if 



these bars were a limit of opportunity rather than a bound- 

 ary of power. No absolute limitation of mental faculty 

 ever is, or ever could be, felt by the creatures whom it af- 

 fects. Of this we have abundant evidence in the lower ani- 

 mals, and in those lower faculties of our own nature which 

 are of like kind to theirs. All their powers and many of 

 our own are exerted without any sense of limitation, and 

 this because of the very fact that the limitation of them is 

 absolute and complete. In their own nature they admit of 

 no larger use. The field of effort and of attainable enjoy- 

 ment is, as regards them, co-extensive with the whole field 

 in view. Nothing is seen or felt by them which may not be 

 possessed. In such possession all exertion ends and all 

 desire is satisfied. This is the law of every faculty subject 

 to a limit which is absolute. In physics, the existence of 

 any pressure is the index of a potential energy which, 

 though it may be doing no work, is yet always capable of 

 doing it. And so in the intellectual world, the sense of 

 pressure and confinement is the index of powers which 

 under other conditions are capable of doing what they can- 

 not do at present. It is in these conditions that the barrier 

 consists, and at least to a large extent the)' are external. 

 What we feel, in short, is less an incapacity than a restraint. 



So much undoubtedly is to be said as to the nature of 

 those limitations on our mental powers of which we are 

 conscious. And the considerations thus presented to us 

 are of immense importance in qualifying the conclusions to 

 be drawn from the facts of consciousness. They do not 

 justify', although they may account for, any feeling of 

 despair as to the ultimate accessibility of that knowledge 

 which we so much desire. On the contrary, the)' suggest 

 the idea that there is within us a Reserve of Power to some 

 unknown and indefinite extent. It is as if we could under- 

 stand indefinitely more than we can discover, if only some 

 higher Intelligence would explain it to us. 



But if it is of importance to take note of this Reserve of 

 Power of which we are conscious in ourselves, it is at least 

 of equal importance to estimate aright the conceptions to 

 which we can and do attain without drawing upon this re- 

 serve at all. Not only are the bars confining us bars which 

 we can conceive removed, but they are bars which in cer- 

 tain directions offer no impediment at all to a boundless 

 range of vision. Perhaps there is no subject on which the 

 fallacies of philosophic phraseology have led to greater 

 errors. "That the Finite cannot comprehend the Infinite," 

 is a proposition constantly propounded as an undoubted 

 and all-comprehensive truth. Such truth as does belong to 

 it seems to come from the domain of Physics, in which it 

 represents the axiom that a part cannot be equal to the 

 whole. From this, in the domain of Mind, it comes to rep- 

 resent the truth, equally undeniable, that we cannot know 

 all that Infinity contains. But the meaning into which it is 

 liable to pass when applied to Mind is that Man cannot con- 

 ceive Infinity. And never was any proposition so commonly 

 accepted which, in this sense, is so absolutely devoid of all 

 foundation. Not only is Infinity conceivable by us, but it 

 is inseparable from conceptions which are of all others the 

 most familiar. Both the great conceptions of Space and 

 Time are, in their very nature, infinite. We cannot con- 

 ceive of either of these as subject to limitation. We cannot 

 conceive of a moment after which there shall be no more 

 Time, nor of a boundary beyond which there is no more 

 Space. This means that we cannot but think of Space as in 

 finite, and of Time as everlasting. 



If these two conceptions stood alone they would be 

 enough, for in regard to them the only incapacity under 

 which we labor is the incapacity to conceive the Finite. For 

 all the divisions of Space and Time with which we are 

 so familar, — our days and months and years, and our vari- 

 ous units of distance, — we can only think of as bits and 

 fragments of a whole which is illimitable. But although 

 these great conceptions of Space and Time are possibly the 

 only conceptions to which the idea of infinity attaches as an 

 absolute necessity of Thought, they are by no means the 

 only conceptions to which the same idea can be attached, 

 and probably ought to be so. The conception of Matter is 

 one, and the conception of Force is another, to which we 

 do not perhaps attach, as of necessity, the idea of inde- 

 structibility, or the idea of eternal existence and of infinite 

 extension. But it is remarkable that in exact proportion as 

 I science advances, we are coming to understand that both of 



