图书图片
PDF
ePub

III.

And nothing is more true than that such was the CHAP. cautious and patient course of inquiry prescribed by him to all the genuine disciples of his inductive method. But he was far from being one of those humble philosophers who would limit human science to the enumeration of particular facts. He had, on the contrary, vast hopes of the human intellect under the guidance of his new logic. The Latens Schematismus, or intrinsic configuration of bodies, the Latens processus ad formam, or transitional operation through which they pass from one form, or condition of nature, to another, would one day, as he hoped, be brought to light; and this not, of course, by simple observation of the senses, nor even by assistance of instruments, concerning the utility of which he was rather sceptical, but by a rigorous application of exclusive and affirmative propositions to the actual phænomena by the inductive method. "It appears," says Playfair, "that Bacon placed the ultimate object of philosophy too high, and too much out of the reach of man, even when his exertions are most skilfully conducted. He seems to have thought, that by giving a proper direction to our researches, and carrying them on according to the inductive method, we should arrive at the knowledge of the essences of the powers and qualities residing in bodies; that we should, for instance, become acquainted with the essence of heat, of cold, of colour, of transparency. The fact however is that, in as far as science has yet advanced, no one essence has been discovered, either as to matter in general, or as to any of its more extensive modifications. We are yet in doubt

CHAP.
III.

Almost justified of late;

whether heat is a peculiar motion of the minute parts of bodies, as Bacon himself conceived it to be, or something emitted or radiated from their surfaces, or, lastly, the vibrations of an elastic medium by which they are penetrated and surrounded."

63. It requires a very extensive survey of the actual dominion of science, and a great sagacity to judge, even in the loosest manner, what is beyond the possible limits of human knowledge. Certainly, since the time when this passage was written by Playfair, more steps have been made towards realizing the sanguine anticipations of Bacon than in the two centuries that had elapsed since the publication of the Novum Organum. We do not yet know the real nature of heat, but few would pronounce it impossible or even unlikely that we may know it, in the same sense that we know other physical realities not immediately perceptible, before many years shall have expired. The atomic theory of Dalton, the laws of crystalline substances discovered by Häuy, the development of others still subtler by Mitscherlich, instead of exhibiting, as the older philosophy had done, the idola rerum, the sensible appearances of concrete substance, radiations from the internal glory, admit us, as it were, to stand within the vestibule of nature's temple, and to gaze on the very curtain of the shrine. If indeed we could know the internal structure of one primary atom, and could tell, not of course by immediate testimony of sense, but by legitimate inference from it, through what constant laws its component molecules, the atoms of atoms, attract, retain, and repel each other, we should have before

III.

our mental vision not only the Latens Schematismus, CHAP. the real configuration of substances, but their form, or efficient nature, and could give as perfect a definition of any one of them, of gold for example, as we can of a cone or a parallelogram. The recent discoveries of animal and vegetable development, and especially the happy application of the microscope to observing chemical and organic changes in their actual course, are equally remarkable advances towards a knowledge of the Latens processus ad formam, the corpuscular motions by which all change must be accomplished, and are in fact a great deal more than Bacon himself would have deemed possible.*

be kept

bounds.

64. These astonishing revelations of natural mys- but should teries, fresh tidings of which crowd in upon us within every day, may be likely to overwhelm all sober hesitation as to the capacities of the human mind, and to bring back that confidence which Bacon, in so much less favourable circumstances, has ventured to feel. There seem however, to be good reasons for keeping within bounds this expectation of future improvement, which, as it has sometimes been announced in unqualified phrases, is hardly more philosophical than the vulgar supposition that the capacities of mankind are almost stationary. The phænomena of nature indeed, in all their possible combinations, are so infinite, in a popular

By the Latens processus, he meant only what is the natural operation by which one form or condition of being is induced upon another. Thus, when the surface of iron becomes rusty, or when

water is converted into steam, some
change has taken place, a latent
progress from one form to another.
This, in numberless cases, we can
now answer, at least to a very great
extent, by the science of chemistry.

CHAP.
III.

Limits to our knowledge by seuse.

sense of the word, that during no period, to which the human species can be conceived to reach, would they be entirely collected and registered. The case is still stronger as to the secret agencies and processes by means of which their phænomena are displayed. These have as yet, in no one instance, so far as I know, been fully ascertained. "Micro

scopes," says Herschel, "have been constructed which magnify more than one thousand times in linear dimension, so that the smallest visible grain of sand may be enlarged to the appearance of one million times more bulky; yet the only impression we receive by viewing it through such a magnifier is that it reminds us of some vast fragment of a rock; while the intimate structure on which depend its colour, its hardness, and its chemical properties, remains still concealed; we do not seem to have made even an approach to a closer analysis of it by any such scrutiny."*

65. The instance here chosen is not the most favourable for the experimental philosopher. He might perhaps hope to gain more knowledge by applying the best microscope to a regular crystal or to an organised substance. And it is impossible not to regret that the great discovery of the solar microscope has been either so imperfectly turned to account by philosophers, or has disappointed their hopes of exhibiting the mechanism of nature with the distinctness they require. But there is evidently a fundamental limitation of physical science, arising from those of the bodily senses and of mus

* Discourse on Nat. Philos. p. 191.

III.

cular motions. The nicest instruments must be CHAP. constructed and directed by the human hand; the range of the finest glasses must have a limit not only in their own natural structure but in that of the human eye. But no theory in science will be acknowledged to deserve any regard, except as it is drawn immediately, and by an exclusive process, from the phænomena which our senses report to us. Thus the regular observation of definite proportions in chemical combination has suggested the atomic theory; and even this has been sceptically accepted by our cautious school of philosophy. If we are ever. to go farther into the molecular analysis of substances, it must be through the means and upon the authority of new discoveries exhibited to our senses in experiment. But the existing powers of exhibiting or compelling nature by instruments, vast as they appear to us, and wonderful as has been their efficacy in many respects, have done little for many years past in diminishing the number of substances reputed to be simple; and with strong reasons to suspect that some of these, at least, yield to the crucible of nature, our electric batteries have up to this hour played innocuously round their heads.

66. Bacon has thrown out, once or twice, a hint at a single principle, a summary law of nature, as if all subordinate causes resolved themselves into one great process, according to which God works his will in the universe: Opus quod operatur Deus a principio usque ad finem. The natural tendency towards simplification, and what we consider as harmony, in our philosophical systems, which Lord Bacon

« 上一页继续 »