"We come back again, therefore, to the question, What was the radical and fatal defect in the physical speculations of the Greek philosophical schools?

"To this I answer: The defect was, that though they had in their possession facts and ideas, the ideas were not appropriate to the facts.

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"The peculiar characters of scientific ideas, which I have endeavoured to express by speaking of them as distinct and appropriate to the facts, must be more fully and formally set forth when we come to the philosophy of the subject. In the mean

time the reader will probably have no difficulty in conceiving that for each class of facts there is some special set of ideas, by means of which the facts can be included in general scientific truths: and that these ideas, which may be thus termed appropriate, must be possessed with entire distinctness and clearness, in order that they may be successfully applied. It was the want of such ideas having reference to material phenomena, which rendered ancient philosophers with very few exceptions helpless and unsuccessful speculators on physical subjects.

"This must be illustrated by one or two examples. One of the facts which Aristotle endeavours to explain is this: that when the sun's light passes through a hole, whatever be the form of the hole, the bright image, if formed at any considerable distance from the hole, is round, instead of imitating the figure of the hole, as shadows resemble their objects. We shall easily perceive this appearance to be a necessary consequence of the circular figure of the sun, if we conceive light to be diffused from the luminary by means of straight rays proceeding,

from every point. But instead of this appropriate idea of rays, Aristotle attempts to explain the fact by saying that the sun's light has a circular nature, which it always tends to manifest. And this vague and loose conception of a circular quality, employed instead of the distinct conception of rays, which is really applicable, prevented Aristotle from giving a true account even of this very simple optical phenomenon."

With all due submission to Dr. Whewell we must say that this explanation seems to us nothing more than answering the question by the question itself, put in another form. It is simply saying that the Greeks failed in their attempts to construct science because they had not fit scientific ideas; that they could not correctly explain phenomena, because they were not in possession of the correct explanations. This looks very like a truism.

The question was not, Had the Greeks appropriate (true) ideas? The fact that they had not such ideas was apparent in their failure. The question asked by Dr. Whewell himself was, What was the cause of their failure? And it will be readily admitted that no explanation of a cause can be given by simply stating, in a circumlocutory manner, the very fact to be explained.

Can we have misunderstood Dr. Whewell? Scarcely; his language is plain and decisive; the only possible ambiguity must be in the phrase 66 appropriate ideas." In his subsequent work The Philosophy of the Inductive Sciences,' he is at some pains to explain what he understands by the phrase. He says very justly that "no genuine

'Hist. of Ind. Sciences,' i. p. 79.

advance could ever be obtained in mechanics by applying to the subjects the ideas of space and time merely no advance in chemistry by the use of mere mechanical conceptions: no discovery in physiology by referring facts to mere chemical and mechanical principles." This is very true, and adapted to his purpose; but does not, we imagine, in any way bear out his previous remarks on Greek philosophy.

In the first place, it is by no means true that the Greeks always applied "inappropriate ideas," even when in error. Their generalizations were too hasty, and here mainly was the cause of their errors.* In the second place, we have still to learn the reasons which caused them to apply inappropriate ideas, if we would learn the cause of their failure. Men of vast intellectual powers fail in discerning the real connections of phenomena. The question is, why did they fail?

The Greeks failed, we believe, because they sought false objects, and employed a false method; because they made science a part of metaphysics; and when pursuing science for science's sake, they employed a wrong method. They did not acquire

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appropriate ideas," because with such objects, and with such a method, they could not acquire

Since writing this we have read the following confirmation by Dr. Whewell's reviewer:-"Aristotle gives no such explanation as that which is ascribed to him. He never mentions the circular nature of the sun's light; and he gives an explanation of the phenomenon which it is manifest Mr. W. could not have given, and which would not have done discredit to Newton himself. Aristotle not only applies the appropriate idea of rectilinear rays, but he does much more, he proves that the phenomenon is not deducible from this idea."-Edin. Rev., Jan. 1842.

them. And the few scientific ideas they did acquire were due either to mathematics or to an empirical, consequently an unscientific, method.

This answer is no novelty of ours; it is that which the best thinkers have given; it is that which a careful inspection of ancient theories must at once suggest. If it be correct, we shall easily assign to Bacon his historical position; if it be incorrect, and if Dr. Whewell's opinion be accepted, it will be difficult to say what place Bacon fills in the history of science: he certainly did not leave mankind a rich inheritance of "appropriate ideas;" but he left mankind the rich inheritance of a method" that being by these our aids and appliances freed and defended from wanderings and impediments, men may lend their hands also to the labours which remain to be performed." He did not teach men appropriate ideas, but he taught them how they might acquire them.

CHAPTER III.

BACON'S METHOD.

THIS chapter will be purely expository; and as the exposition of Bacon's method has been given by Professor Playfair, in his "Dissertation on the Progress of Physical Science," so clearly and so fully as to leave nothing to desire, we shall simply abridge it.

Before laying down the rules of his method Bacon proceeds to enumerate the causes of errorthe Idols, as he terms them, in his figurative language, or false divinities to which the mind had so long been accustomed to bow.* He considered this enumeration as the more necessary, that the same idols were likely to return, even after the reformation of science.

1. The Idols of the Tribe are the causes of error founded on human nature in general. "The mind," he observes, "is not like a plane mirror,

* Mr. Hallam was the first to point out the mistake which all modern writers have made respecting the meaning of the word Idol, as used by Bacon; which does not mean idol, but false appearance (eidwλov). See the passage in Hallam's Lit. of Europe, vol. iii. pp. 194–6.