PROPOSITIONS DERIVED FROM SENSATION.

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propositions containing the result of our perceptions respecting them are true. We hesitate as little about propositions significant of the reality of our bodily feelings, and of our desires to gratify them; such as, that hunger, thirst, pain, are uneasy sensations, from which all men wish to be relieved, and that rest after fatigue is a source of pleasure. In all these cases, no means of conviction are presented to the mind, besides perceptions and feelings. The knowledge, accordingly, derived from this source, is often called the dictates of sense; and the sentences that denote it are sometimes termed sensible propositions.

I have observed, that no man, in mixing with the world, or when engaged in business, can permit himself one moment to discredit the evidence of his senses, or to disbelieve the information he receives through that channel. Some philosophers, however, in speculation, have ventured to question the credibility of this evidence, and have not scrupled to conclude, that from any thing we know, all the splendid exhibitions of nature and art, with which the world abounds, may be no more than phantoms of the imagination, a magnificent display of ideal scenery without reality. They have applied a similar theory to the evidence of internal sensation or consciousness, and, finding it equally unworthy of credit, they have ventured to annihilate the immaterial world also; and thus, banishing both matter and spirit from the universe, they have left in nature nothing of real existence but ideas and imaginary powers to prompt these ideas. A philosophy so bold and tremendous in its consequences, cannot fail to excite a little our curiosity; and as it has subsisted long in the world, and has attracted a good deal of attention, some account of it may be expected.*

[* The account, given by the author, of the speculations of Aristotle, Epicurus, Locke, Hume, and others, is here omitted, as belonging more appropriately to a general work on mental science.-Ed.]

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PROPOSITIONS DERIVED FROM CONSCIOUSNESS.

LECTURE V.

PROPOSITIONS DERIVED FROM CONSCIOUSNESS, INTUITION, REA

SONING, TESTIMONY-INFERENCE OR REASONING IN GENERAL

-PREJUDICES.

CONSCIOUSNESS is a copious source of knowledge, and furnishes evidence of the truth of a numerous class of propositions. By it we gain an acquaintance with the human constitution, particularly with the important operations of the understanding, the imagination, and the passions. If I affirm that the imagination is pleased with a fine prospect, a beautiful landscape, an elegant exhibition of art, whether in writing, painting, statuary, or architecture; if I assert that the understanding is delighted with the discovery of truth on all subjects, and in all degrees, from the lowest stage of probability to the most triumphant evidence of intuition or demonstration; if I maintain that all our passions were given us for wise and good purposes; that all the gratifications of them, within the limits prescribed by reason and virtue, are pleasant, salutary, and commendable; and that all irregular gratifications are not only improper in themselves, but are also painful and destructive; I have hardly any proof to produce of the numerous propositions, which express the various cases into which these views of the human mind may be resolved, except an appeal to the consciousness of the person I wish to convince.

If he shall deny that his imagination is captivated with a beautiful scene of nature or art; if he shall declare that his understanding receives no pleasure in the discovery of truth; or that the gratification of a regular passion yields him no joy, while the agi

PROPOSITIONS SUPPORTED BY CONSCIOUSNESS.

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tation of an irregular one fills him with satisfaction; all I can urge is, that he mistakes his constitution, or that the structure of it is different from that of most other men. But if he persists in maintaining the consciousness of the truth of what he asserts, I can only oppose a contrary consciousness on my part. We must continue of different opinions, for I can produce no arguments to persuade him to adopt my sentiments.

From this view of knowledge it will appear, that many moral and political propositions, many which communicate truth in oratory, poetry, criticism, and business, are principally, if not entirely, supported by consciousness.

If I assert that all men applaud a generous or a grateful action, and detest an unjust or a cruel one; that kings are prone to tyrannize over their subjects, or that the people are disposed to insult and oppose their rulers; that the beauties of eloquence and poetry are felt by all mankind, even the most unpolished and unlearned; that the rules of criticism are nothing more than the theories of emotions and passions; that prudence and industry are the best and surest means of attaining success in business, while folly and idleness are commonly attended with misfortune and contempt; what do I but appeal to consciousness concerning the truth of the propositions I advance? If I gain not immediate assent, all I can do to procure it is, to enumerate examples by which the opinions I maintain have been verified, and to hold forth these as documents of general consciousness in support of the judgment I have formed. In a word, in all these subjects the most satisfactory evidence and the best theories are founded on the nature of the human constitution. The most sagacious and successful moralists, politicians, critics, and observers of human affairs, ground their maxims and their observations on the qualities of the mind, of which they are conscious themselves, or of which they discover that others are conscious.

Intuition is another copious source of knowledge, and communicates conviction of the truth of all those propositions which are denominated self-evident. Intuition is the perception of the agreement or disagreement of two ideas on bare juxtaposition, without the

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INTUITIVE PROPOSITIONS.

intervention of any third idea; and the proposition which expresses our judgment of that agreement or disagreement is said to be supported by intuitive evidence.* All the axioms of mathematics and arithmetic, as, "Two straight lines cannot contain a space,' "Things equal to the same thing are equal to one another," "Two and three are equal to five," "Two and three are not equal to six;" all the principles adopted in physical science, as, "A body cannot be in two places at the same time," "Nothing can produce nothing," "It is impossible for the same thing to be and not to be;" all the maxims relative to identity, as, "Matter is matter," and "Spirit is spirit;" form intuitive propositions. All certain reasoning, commonly called demonstration, must begin with a comparison of two ideas expressed by an intuitive proposition; and every proposition expressive of the agreement of any two intermediate ideas, or of every successive step of the demonstration, must be. intuitive. These are the chief cases of intuitive truth. I must, however, observe, before I leave this topic, that axioms, of which some philosophers seem to be so fond, and which they hold forth as the foundations of all science, appear so far

[* Truths are known to us in two ways: some are known directly, and of themselves; some through the medium of other truths. The former are the subjects of intuition; the latter, of inference. The truths known by intuition are the original premises from which all others are inferred. Our assent to the conclusion being grounded upon the truth of the premises, we never could arrive at any knowledge by reasoning, unless something could be known antecedently to all reasoning.

The object of logic is to ascertain how we come by that portion of our knowledge (much the greatest portion) which is not intuitive; and by what criterion we can, in matters not self-evident, distinguish between things proved and things not proved, between what is worthy and what is unworthy of belief. Of the various questions which the universe presents to our inquiring faculties, some are soluble by direct consciousness, others only by means of evidence. Logic is concerned with these last.-Mills' Logic, pp. 8, 12.]

INUTILITY OF AXIOMS IN REASONING.

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from being such, that no reasoning is ever founded on them, and that they are of no essential use in a course of reasoning. What is an axiom? It is a general proposition, including a number of particular cases, and declarative of an intuitive truth, which truth must be as obvious, when surveyed in any of the particular cases, as in the general proposition; and, if this be true, the axiom cannot be of any use, for the application of it to the particular case can afford no light which the mind did not possess before that application. I shall illustrate this remark by a few examples, which will make it very plain.

If I say that two and three are equal to four and one, I am perfectly satisfied of the equality of these two quantities, before the application of the axiom, that "Things equal to the same thing are equal to one another," and before I add, that they are both equal to five. The axiom adds no light to my conceptions. It does no more than repeat, in general terms, what was expressed more simply, if not more intelligibly, in particular terms. If from two lines, each a mile long, I take away respectively a half mile, I cannot question a moment, that the remaining half miles are equal to one another, although I had never heard of the axiom, "If equals are taken from equals, the remainders will be equal." If from a field of an acre in extent, I take away half an acre, and throw it into an adjacent field, I have the most entire conviction that the extent of the first field will be much less than it was before the division, without having recourse to the axiom, "The whole is greater than a part." If I infer that something must have existed from eternity, because something now exists, my conviction is complete, before I reflect on, or perhaps know, the scholastic maxim, "Ex nihilo nihil fit," "Nothing can produce nothing." If I am certain that the sun is above the horizon, I conclude with entire confidence, that he is not also below it, although I am unacquainted with the axiom, "Bodies cannot be in different places at the same time." If, having two lines, one half a mile, and the other a quarter of a mile long, I add to each a whole mile, I am perfectly satisfied that the new line, composed of the mile and half, is longer than that composed of the mile and the quarter. I procure no additional conviction whatever from the application of