Our next quotation contains Hume's sentence of execution rather than critique upon metaphysics as he saw them in connection with dogmatic theology. First, for his fiery anathema:—
"When we run over libraries, persuaded of these principles, what havoc must we make? If we take in our hand any volume of divinity or School metaphysics, for instance, let us ask, Does it contain any abstract reasoning concerning quantity or number? No. Does it contain any experimental reasoning concerning matters of fact and existence? No. Commit it then to the flames: For it can contain nothing but sophistry and illusion." (Inquiry concerning Human Understanding, § XII.) Alas for certain of Hume's own speculations!
The student of Positivism knows how this fierce invective was echoed and re-echoed by Comte and his followers. They, however, omitted the qualifying word "School," which Hume prefixed to metaphysics. With Comte, metaphysic of every kind was "anathema maranatha"; and even psychology got excommunicated, by way of making "a clean sweep."
Hume, on the contrary, had an idea of what philosophy ought to be, and thus outlined his preparation for a Metaphysic of the Future:—
"The only method of freeing learning, at once, from these abstruse questions, is to inquire seriously into the nature of human understanding, and show, from an exact analysis of its powers and capacity, that it is by no means fitted for such remote and abstruse subjects. We must submit to this fatigue in order to live at ease ever after: and must cultivate true metaphysics with some care, in order to destroy the false and adulterate. Indolence, which, to some persons, affords a safeguard against this deceitful philosophy, is, with others, overbalanced by curiosity; and despair, which at some moments prevails, may give place afterwards to sanguine hopes and expectations. Accurate and just reasoning is the only catholic remedy, fitted for all persons and all dispositions; and is alone able to subvert that abstruse philosophy and metaphysical jargon, which, being mixed up with popular superstition, renders it in a manner impenetrable to careless reasoners, and gives it the air of science and wisdom.
"Besides this advantage of rejecting, after deliberate inquiry, the most uncertain and disagreeable part of learning, there are many positive advantages, which result from an accurate scrutiny into the powers and faculties of human nature. It is remarkable concerning the operations of the mind, that though most intimately present to us, yet, whenever they become the object of reflection, they seem involved in obscurity; nor can the eye readily find those lines and boundaries which discriminate and distinguish them. The objects are too fine to remain long in the same aspect or situation, and must be apprehended, in an instant, by a superior penetration, derived from nature, and improved by habit and reflection. It becomes, therefore, no inconsiderable part of science barely to know the different operations of the mind, to separate them from each other, to class them under their proper heads, and to correct all that seeming disorder in which they lie involved, when made the object of reflection and inquiry. This task of ordering and distinguishing, which has no merit when performed with regard to external bodies, the objects of our senses, rises in its value when directed towards the operations of the mind, in proportion to the difficulty and labour which we meet with in performing it. And if we can go no farther than this mental geography, or delineation of the distinct parts and powers of the mind, it is at least a satisfaction to go so far; and the more obvious this science may appear (and it is by no means obvious), the more contemptible still must the ignorance of it be esteemed, in all pretenders to learning and philosophy." Ibid. Section I.
It seems worth while to consider what the effects might have been, had Hume been faithful to his own idea.[46] In the first place he would have remedied the weakness pointed out by Macaulay in the premises of the schoolmen, which were in fact little better than sententious maxims often derived from mistranslated passages of Scripture, one-sided opinions of the Fathers, and other sources of doubtful value. These, Hume would have abscided altogether, and rested his "true metaphysics" upon such principles as survived a searching inquiry into the conditions of Human knowledge. Hence, secondly, he would have rendered a great service to Divinity itself, which can never be benefited by such arguments as have been described, but must look for a safe alliance to a synthesis of Faith and Reason. And in the third place he might have probably given to his country a critical Philosophy adapted to English modes of Thought. Kant's mind was fired by a spark of Hume's kindling, but when we think what might have been the shape and acceptance of Kant in this country had Hume heralded him by a critique of Reason, it is impossible to read the great Scotchman's writings without a feeling of disappointment.[47]
It would however be unjust to omit the fact that Hume did really entertain a serious intention of dealing with these difficult questions. Thus much is expressed in his earliest work, and we may conjecture that literary disappointment was at least one cause of that later preference for "easy philosophy" which contrasts so strongly with the programme of his treatise on Human Nature. Few programmes were ever more vigorously outlined, than the ensuing.
"From hence," he says, "in my opinion, arises that common prejudice against metaphysical reasonings of all kinds, even amongst those who profess themselves scholars, and have a just value for every other part of literature. By metaphysical reasonings, they do not understand those on any particular branch of science, but every kind of argument, which is any way abstruse, and requires some attention to be comprehended. We have so often lost our labour in such researches, that we commonly reject them without hesitation, and resolve, if we must for ever be a prey to errors and delusions, that they shall at least be natural and entertaining. And, indeed, nothing but the most determined scepticism, along with a great degree of indolence, can justify this aversion to metaphysics. For, if truth be at all within the reach of human capacity, 'tis certain it must lie very deep and abstruse; and to hope we shall arrive at it without pains, while the greatest geniuses have failed with the utmost pains, must certainly be esteemed sufficiently vain and presumptuous. I pretend to no such advantage in the philosophy I am going to unfold, and would esteem it a strong presumption against it, were it so very easy and obvious."—Treatise on Human Nature, Introduction, p. 12.
In these sentences Hume has sufficiently condemned the vulgar objections brought against abstract reasoning. Deep and difficult questions can be discussed in no other manner; and what is often called a popular treatise on some subject of philosophic inquiry can never be more than a statement of its writer's opinions, or possibly of his sentimental prejudices.