from natural philosophy such rules as would have guarded the logician from the 'chief errors' into which he may fall?
Dr. Whately informs us, indeed, that logic furnishes certain syllogistic forms to which all sound arguments may be reduced, and thus establishes universal tests for the detection of fallacy—but it is to be observed that it is only such fallacy as may creep in between the premises and the conclusion of an argument. It is to this narrow and Aristotelian object that logic is restricted. 'The process of reasoning itself is alone the appropriate province of logic. This process will have been correctly conducted if it have conformed to the logical rules, which preclude the possibility of any error creeping in between the principles from which we are arguing, and the conclusions we deduce from them.'* We learn from our authority, that as arithmetic does not profess to introduce any notice of the things, whether coins, persons, or dimensions, respecting which calculations are made; neither does logic undertake 'the ascertainment of facts, or the degree of evidence of doubtful propositions.' And just as an arithmetical result will be useless if the data of the calculation be incorrect, so a logical conclusion is liable to be false if the premises are so. Neither does the logic, now under consideration, concern itself with the 'discovery of truth,' excepting so far as that may be said to be implied by the detection of error in a false inference.** Logic thus, confined to the actual process of reasoning, however important its functions there, evidently leaves us in the dark as to the value of what we reason about. For the information thus missing, this logic refers us to knowledge in general—to grammar and composition for the art of expressing, with correctness and perspicuity, the terms of propositions—to natural, moral, political, or other philosophy, for the facts which alone can establish the truth of the premises reasoned from.
* Intro., p. 13.
** For the grounds of these representations, see
Dissertation on the Province of Reasoning, chap. 2, sec. 4
Dr. Whately's Logic.
The exclusion from logic of all consideration of the facts on which propositions are founded, is thus endeavoured to be justified by the Archbishop of Dublin:—'No arithmetical skill will secure a correct result, unless the data are correct from which we calculate: nor does any one on that account undervalue arithmetic; and yet the objection against logic rests on no better foundation.' This is true, but is it true that arithmetic is on this account to be imitated? If the arithmetician must take his data for granted, it is what the searcher after truth must never do—he must use his eyes and examine for himself, in all cases, as far as possible, unless he intends to be deceived. And for want of such precaution as this, the arithmetician is at sea the moment he steps out of the narrow path of mechanical routine. Who is not aware of the failures of calculation when applied to the general business of life—to statistics, moral and political? Every day, facts have to be called in to correct the egregious blunders of figures.* The calculations are conducted in most approved form, but are of no use. Does not this demonstrate that when arithmetic, like logic, is applied to the business of life, general rules for securing the accuracy of data would be of essential service? Supposing, however, that arithmetic could do very well without them, does it follow that logic should, when it would be safer and more efficient with them?
* 'In Art, in Practice, innumerable critics will demonstrate
that most things are impossible. It was proved by fluxionary
calculus, that steam-ships could never get across from the
farthest point of Ireland to the nearest of Newfoundland;
impelling force, resisting force, maximum here, minimum
there; by law of Nature, and geometric demonstration—what
could be done? The Great Western could weigh anchor from
Bristol Port; that could be done. The Great Western,
bounding safe through the gullets of the Hudson, threw her
cable out on the capstan of New York, and left our still
moist paper-demonstration to dry itself at leisure.'—
Thomas Carlyle, Chartism, pp. 96–7.
Since our author's canons are held absolute in the schools, it may be useful to consider this last cited argument in another light. A stronger objection may be urged, one which particularly addresses itself to those who mistake mere pertinence for general relevance, and suppose that a single analogy decides a case.
His Grace reasons, that, because arithmetic does not concern itself about its data, logic should follow the same example. But why overlooks he pure mathematics—a much higher science than arithmetic? Surely geometry, which through all time has been the model of the sciences, was better worthy than arithmetic to be the model of logic! Was it classical in the principal of St. Alban's College to abandon Euclid and cleave unto Cocker or Walkingame?
Arithmetic is mechanical—geometry is reasoning; surely it was more befitting to compare reason with reason, when endeavouring to discover the true way of perfecting reason. Geometry is, of all sciences, reputed the most conclusive in its arguments—and we know it is distinguished above all sciences for carefulness in its data. It begins with axioms, the most indubitable of all data, and its subsequent conclusions are founded only on established facts—and to be sure that they are established facts, the geometer, before he employs them, establishes them himself. If an analogy is to decide the province of logic, here is an analogy whose pretensions over those of arithmetic are eminent.
So conclusive did Dr. Whately deem the argument just examined, that he many times, in various forms, reproduced it. One of the last instances is under the head of 'Fallacies.' 'It has been made a subject of bitter complaint against logic, that it presupposes the most difficult point to be already accomplished; viz., the sense of the terms to be ascertained. A similar objection might be urged against every other art in existence e.g., against agriculture, that all the precepts for the cultivation of land presuppose the possession of a farm.'*
* Logic, chap. 3. Fallacies, sec. 2.
Already has been pointed out what may reasonably induce a suspicion of the soundness of these analogies; viz., that their author found it necessary to disregard them and introduce, from other branches of knowledge, certain disquisitions on the 'sense of terms.' With regard to this particular instance, it may be observed, that though treatises on agriculture do presuppose the possession of a farm, they do not presuppose the knowledge requisite for cultivating it, but inform fully of soil, and seed, and crops. So logic may be allowed to presuppose the existence of the universe, whence truth is drawn, or the existence of language, 'whereby it is expressed; but it is surely not to pre-suppose the knowledge of facts and terms, the great instruments for the cultivation of truth. Agricultural treatises hardly warrant this inference. There are the representations that induced the confession that 'Logic is not so much an instrument of acquirement as of defence. It is a good armour to buckle on when compelled to battle for our heritage, but a poor implement for its cultivation.'*
All practical arts include a knowledge of materials as well as implements. Platers, ignorant of the nature of metals, cabinetmakers, of the different species of wood, make but sorry artizans; and in like manner, reasoners, unacquainted, at least in a general way, with the accuracy of what is reasoned about, make but sorry logicians.**
It will readily be expected that in the modern progress of knowledge, the Aristotelian province of logic would be enlarged. The far-seeing intellect of Lord Verulam heralded the innovation—'Our glorious Bacon led philosophy forth from the jargon of schools and the fopperies of sects. He made her to be—the handmaid of nature, friendly to her creatures, and faithful
