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 himself reckons among the idola tribûs, the fallacies incident to the species, has led some to favour this unity of physical law. Impact and gravity have each had their supporters. But we are as yet at a great distance from establishing such a generalization, nor does it appear by any means probable that it will ever assume any simple form.
Inductive logic; whether confined to physics. 67. The close connexion of the inductive process recommended by Bacon with natural philosophy in the common sense of that word, and the general selection of his examples for illustration from that science, have given rise to a question, whether he comprehended metaphysical and moral philosophy within the scope of his inquiry.[209] That they formed a part of the Instauration of Sciences, and therefore of the Baconian philosophy in the fullest sense of the word, is obvious from the fact that a large proportion of the treatise De Augmentis Scientiarum is dedicated to those subjects; and it is not less so that the idola of the Novum Organum are at least as apt to deceive us in moral as in physical argument. The question, therefore, can only be raised as to the peculiar method of conducting investigations, which is considered as his own. This would, however, appear to have been decided by himself in very positive language. “It may be doubted, rather than objected, by some, whether we look to the perfection, by means of our method, of natural philosophy alone, or of the other sciences also, of logic, of ethics, of politics. But we certainly mean what has here been said, to be understood as to them all; and as the ordinary logic, which proceeds by syllogism, does not relate to physical only, but to every other science; so ours, which proceeds by induction, comprizes them all. For we as much collect a history and form tables concerning anger, fear, shame and the like, and also concerning examples from civil life, and as much concerning the intellectual operations of memory, combination and partition, judgment and the others, as concerning heat and cold, or light, or vegetation, or such things.”[210] But he proceeds to intimate, as far as I understand the next sentence, that, although his method or logic, strictly speaking, is applicable to other subjects, it is his immediate object to inquire into the properties of natural things, or what is generally meant by physics. To this indeed the second book of the Novum Organum, and the portions that he completed of the remaining parts of the Instauratio Magna bear witness.
[209] This question was discussed some years since by the late editor of the Edinburgh Review on one side, and by Dugald Stewart on the other. See Edinburgh Review, vol. iii. p. 273, and the Preliminary Dissertation to Stewart’s Philosophical Essays.
[210] Etiam dubitabit quispiam potius quam objiciet, utrum nos de naturali tantum philosophia, an etiam de scientiis reliquis, logicis, ethicis, politicis, secundum viam nostram perficiendis loquamur. At nos certè de universis hæc, quæ dictasunt, intelligimus; atque quemadmodum vulgaris logica, quæ regit res per syllogismum, non tantum ad naturales, sed ad omnes scientias pertinet, ita et nostra, quæ procedit per inductionem, omnia complectitur. Tam enim Historiam et Tabulas Inveniendi conficimus de ira, metu et verecundia et similibus, ac etiam de exemplis rerum civilium; nec minùs de motibus mentalibus memoriæ, compositionis et divisionis, judicii et reliquorum, quam de calido et frigido, aut luce, aut vegetatione aut similibus. Sed tamen cum nostra ratio interpretandi, post historiam præparatam et ordinatam, non mentis tantum motus et discursus, ut logica vulgaris, sed et rerum naturam intueatur, ita mentem regimus ut ad rerum naturam se aptis per omnia modis applicare possit. Atque propterea multa et diversa in doctrina interpretationis præcipimus. quæ ad subjecti, de quo inquirimus, qualitatem et conditionem modum inveniendi nonnulla ex parte applicent. Nov. Org. i. 127.
Baconian philosophy built on observation and experiment. 68. It by no means follows, because the leading principles of the inductive philosophy are applicable to other topics of inquiry than what is usually comprehended under the name of physics, that we can employ all the prærogativæ instantiarum, and still less the peculiar rules for conducting experiments which Bacon has given us, in moral, or even psychological disquisitions. Many of them are plainly referrible to particular manipulations, or at most to limited subjects of chemical theory. And the frequent occurrence of passages which show Lord Bacon’s fondness for experimental processes, seem to have led some to consider his peculiar methods as more exclusively related to such modes of inquiry than they really are. But when the Baconian philosophy is said to be experimental, we are to remember that experiment is only better than what we may call passive observation, because it enlarges our capacity of observing with exactness and expedition. The reasoning is grounded on observation in both cases. In astronomy, where nature remarkably presents the objects of our observation without liability to error or uncertain delay, we may reason on the inductive principle as well as in sciences that require tentative operations. The inference drawn from the difference of time in the occultation of the satellites of Jupiter at different seasons, in favour of the Copernican theory and against the instantaneous motion of light, is an induction of the same kind with any that could be derived from an experimentum crucis. It is an exclusion of those hypotheses which might solve many phænomena, but fail to explain those immediately observed.
Advantages of the latter. 69. But astronomy, from the comparative solitariness, if we may so say, of all its phænomena, and the simplicity of their laws, has an advantage that is rarely found in sciences of mere observation. Bacon justly gave to experiment, or the interrogation of nature, compelling her to give up her secrets, a decided preference whenever it can be employed; and it is unquestionably true that the inductive method is tedious, if not uncertain, when it cannot resort to so compendious a process. One of the subjects selected by Bacon in the third part of the Instauration as specimens of the method by which an inquiry into nature should be conducted, the History of Winds, does not greatly admit of experiments; and the very slow progress of meteorology, which has yet hardly deserved the name of a science, when compared with that of chemistry or optics, will illustrate the difficulties of employing the inductive method without their aid. It is not, therefore, that Lord Bacon’s method of philosophising is properly experimental, but that by experiment it is most successfully displayed.
Sometimes applicable to philosophy of human mind. 70. It will follow from hence that in proportion as, in any matter of inquiry, we can separate, in what we examine, the determining conditions, or law of form, from everything extraneous, we shall be more able to use the Baconian method with advantage. In metaphysics, or what Stewart would have called the philosophy of the human mind, there seems much in its own nature capable of being subjected to the inductive reasoning. Such are those facts which, by their intimate connection with physiology, or the laws of the bodily frame, fall properly within the province of the physician. In these, though exact observation is chiefly required, it is often practicable to shorten its process by experiment. And another important illustration may be given from the education of children, considered as a science of rules deduced from observation; wherein also we are frequently more able to substitute experiment for mere experience, than with mankind in general, whom we may observe at a distance, but cannot control. |Less so to politics and morals.| In politics, as well as in moral prudence, we can seldom do more than this. It seems however practicable to apply the close attention enforced by Bacon, and the careful arrangement and comparison of phænomena, which are the basis of his induction, to these subjects. Thus, if the circumstances of all popular seditions recorded in history were to be carefully collected with great regard to the probability of evidence, and to any peculiarity that may have affected the results, it might be easy to perceive such a connection of antecedent and subsequent events in the great plurality of instances, as would reasonably lead us to form probable inferences as to similar tumults when they should occur. This has sometimes been done, with less universality, and with much less accuracy than the Baconian method requires, by such theoretical writers on politics as Machiavel and Bodin. But it has been apt to degenerate into pedantry, and to disappoint the practical statesman, who commonly rejects it with scorn; partly because civil history is itself defective, seldom giving a just view of events, and still less frequently of the motives of those concerned in them; partly because the history of mankind is far less copious than that of nature, and in much that relates to politics, has not yet had time to furnish the groundwork of a sufficient induction; but partly also from some distinctive circumstances, which affect our reasonings in moral far more than in physical science, and which deserve to be considered, so far at least as to sketch the arguments that might be employed.
Induction less conclusive in these subjects. 71. The Baconian logic, as has been already said, deduces universal principles from select observation, that is, from particular, and, in some cases of experiment, from singular instances. It may easily appear to one conversant with the syllogistic method less legitimate than the old induction which proceeded by an exhaustive enumeration of particulars, and at most warranting but a probable conclusion. The answer to this objection can only be found in the acknowledged uniformity of the laws of nature, so that whatever has once occurred will, under absolutely similar circumstances, always occur again. This may be called the suppressed premise of every Baconian enthymem, every inference from observation of phænomena, which extends beyond the particular case. When it is once ascertained that water is composed of one proportion of oxygen to one of hydrogen, we never doubt but that such are its invariable constituents. We may repeat the experiment to secure ourselves against the risk of error in the operation or of some unperceived condition that may have affected the result; but when a sufficient number of trials has secured us against this, an invariable law of nature is inferred from the particular instance; nobody conceives that one pint of pure water can be of a different composition from another. All men, even the most rude, reason upon this primary maxim; but they reason inconclusively from misapprehending the true relations of cause and effect in the phænomena to which they direct their attention. It is by the sagacity and ingenuity with which Bacon has excluded the various sources of error, and disengaged the true cause, that this method is distinguished from that which the vulgar practise.
Reasons for this difference. 72. It is required, however, for the validity of this method, first that there should be a strict uniformity in the general laws of nature, from which we can infer that what has been will, in the same conditions, be again; and secondly, that we shall be able to perceive and estimate all the conditions with an entire and exclusive knowledge. The first is granted in all physical phænomena; but in those which we cannot submit to experiment, or investigate by some such method as Bacon has pointed out, we often find our philosophy at fault for want of the second. Such is at present the case with respect to many parts of chemistry; for example, that of organic substances, which we can analyse, but as yet can in very few instances recompose. We do not know, and, if we did know, could not perhaps command, the entire conditions of organic bodies (even structurally, not as living), the form, as Bacon calls it, of blood, or milk, or oak galls. But in attempting to subject the actions of men to this inductive philosophy, we are arrested by the want of both the necessary requisitions. Matter can only be diverted from its obedience to unvarying laws by the control of mind; but we have to inquire whether mind is equally the passive instrument of any law. We have to open the great problem of human liberty, and must deny even a disturbing force to the will before we can assume that all actions of mankind must, under given conditions, preserve the same necessary train of sequences as a molecule of matter. But if this be answered affirmatively, we are still almost as far removed from a conclusive result as before. We cannot without contradicting every day experience, maintain that all men are determined alike by the same exterior circumstances; we must have recourse to the differences of temperament, of physical constitution, of casual or habitual association. The former alone, however, are, at the best, subject to our observation, either at the time, or, as is most common, through testimony; of the latter, no being, which does not watch the movements of the soul itself, can reach more than a probable conjecture. Sylla resigned the dictatorship, therefore all men, in the circumstances of Sylla, will do the same, is an argument false in one sense of the word circumstances, and useless at least in any other. It is doubted by many, whether meteorology will ever be well understood, on account of the complexity of the forces concerned, and their remoteness from the apprehension of the senses. Do not the same difficulties apply to human affairs? And while we reflect on these difficulties, to which we must add those which spring from the scantiness of our means of observation, the defectiveness and falsehood of testimony, especially what is called historical, and a thousand other errors to which the various “idola of the world and the cave” expose us, we shall rather be astonished that so many probable rules of civil prudence have been treasured up and confirmed by experience than disposed to give them a higher place in philosophy than they can claim.
Considerations on the other side. 73. It might be alleged in reply to these considerations, that admitting the absence of a strictly scientific certainty in moral reasoning, we have yet, as seems acknowledged on the other side, a great body of probable inferences, in the extensive knowledge and sagacious application of which most of human wisdom consists. And all that is required of us in dealing either with moral evidence or with the conclusions we draw from it, is to estimate the probability of neither too high; an error from which the severe and patient discipline of the inductive philosophy is most likely to secure us. It would be added by some, that the theory of probabilities deduces a wonderful degree of certainty from things very uncertain, when a sufficient number of experiments can be made; and thus, that events depending upon the will of mankind, even under circumstances the most anomalous and apparently irreducible to principles, may be calculated with a precision inexplicable to any one who has paid little attention to the subject. This, perhaps, may appear rather a curious application of mathematical science, than one from which our moral reasonings are likely to derive much benefit, especially as the conditions under which a very high probability can mathematically be obtained, involve a greater number of trials than experience will generally furnish. It is, nevertheless, a field that deserves to be more fully explored: the success of those who have attempted to apply analytical processes to moral probabilities has not hitherto been very encouraging, inasmuch as they have often come to results falsified by experience; but a more scrupulous regard to all the conditions of each problem may perhaps obviate many sources of error.[211]