PART Of knowledge and we can draw no inference from one object to another, except they be connected by this relation, we may conclude, that there is some error in that reasoning which leads us into such difficulties. probability. This is the objection: let us now consider its solution. 'Tis evident, that whatever is present to the memory, striking upon the mind with a vivacity which resembles an immediate impression, must become of considerable moment in all the operations of the mind, and must easily distinguish itself above the mere fictions of the imagination. Of these impressions or ideas of the memory we form a kind of system, comprehending whatever we remember to have been present, either to our internal perception or senses; and every particular of that system, joined to the present impressions, we are pleased to call a reality. But the mind stops not here. For finding, that with this system of perceptions there is another connected by custom, or, if you will, by the relation of cause or effect, it proceeds to the consideration of their ideas; and as it feels that 'tis in a manner necessarily determined to view these particular ideas, and that the custom or relation, by which it is determined, admits not of the least change, it forms them into a new system, which it likewise dignifies with the title of realities. The first of these systems is the object of the memory and senses; the second of the judgment. 'Tis this latter principle which peoples the world, and brings us acquainted with such existences as, by their removal in time and place, lie beyond the reach of the senses and memory. By means of it I paint the universe in my imagination, and fix my attention on any part of it I please. I form an idea of Rome, which I neither see nor remember, but which is con IX. Of the effects of other relations and nected with such impressions as I remember to have SECT. received from the conversation and books of travellers and historians. This idea of Rome I place in a certain situation on the idea of an object which I call the globe. I join to it the conception of a particular government, and religion and manners. I look backward other habitą. and consider its first foundation, its several revolutions, successes and misfortunes. All this, and every thing else which I believe, are nothing but ideas, though, by their force and settled order, arising from custom and the relation of cause and effect, they distinguish themselves from the other ideas, which are merely the offspring of the imagination. As to the influence of contiguity and resemblance, we may observe, that if the contiguous and resembling object be comprehended in this system of realities, there is no doubt but these two relations will assist that of cause and effect, and infix the related idea with more force in the imagination. This I shall enlarge upon presently. Meanwhile I shall carry my observation a step farther, and assert, that even where the related object is but feigned, the relation will serve to enliven the idea, and increase its influence. A poet, no doubt, will be the better able to form a strong de scription of the Elysian fields, that he prompts his imagination by the view of a beautiful meadow or garden; as at another time he may, by his fancy, place himself in the midst of these fabulous regions, that by the feigned contiguity he may enliven his imagination. But though I cannot altogether exclude the relations of resemblance and contiguity from operating on the fancy in this manner, 'tis observable that, when single, their influence is very feeble and uncertain. As the relation of cause and effect is requisite to persuade us III. PART of any real existence, so is this persuasion requisite to give force to these other relations. For where upon Of the appearance of an impression we not only feign anand other object, but likewise arbitrarily, and of our mere probability good-will and pleasure give it a particular relation to knowledge the impression, this can have but a small effect upon The relation of cause and effect has all the opposite advantages. The objects it presents are fixed and unalterable. The impressions of the memory never change in any considerable degree; and each impression draws along with it a precise idea, which takes its place in the imagination, as something solid and real, IX. certain and invariable. The thought is always deter- SECT. mined to pass from the impression to the idea, and from that particular impression to that particular idea, without any choice or hesitation. Of the effects of other and But not content with removing this objection, I shall relations endeavour to extract from it a proof of the present doc- other habits. trine. Contiguity and resemblance have an effect much inferior to causation; but still have some effect, and augment the conviction of any opinion, and the vivacity of any conception. If this can be proved in several new instances, beside what we have already observed, 'twill be allowed no inconsiderable argument, that belief is nothing but a lively idea related to a present impression. To begin with contiguity; it has been remarked among the Mahometans as well as Christians, that those pilgrims, who have seen Mecca or the Holy Land are ever after more faithful and zealous believers, than those who have not had that advantage. A man, whose memory presents him with a lively image of the Red Sea, and the Desert, and Jerusalem, and Galilee, can never doubt of any miraculous events, which are related either by Moses or the Evangelists. The lively idea of the places passes by an easy transition to the facts, which are supposed to have been related to them by contiguity, and increases the belief by increasing the vivacity of the conception. The remembrance of these fields and rivers has the same influence on the vulgar as a new argument, and from the same causes. We may form a like observation concerning resemblance. We have remarked, that the conclusion which we draw from a present object to its absent cause or effect, is never founded on any qualities which we observe in that object, considered in itself; or, in other III. PART words, that 'tis impossible to determine otherwise than by experience, what will result from any phenomenon, Of or what has preceded it. But though this be so evident knowledge in itself, that it seemed not to require any proof, yet probability. some philosophers have imagined that there is an ap and parent cause for the communication of motion, and that, a reasonable man might immediately infer the motion of one body from the impulse of another, without having recourse to any past observation. That this opi nion is false will admit of an easy proof. For if such an inference may be drawn merely from the ideas of body, of motion, and of impulse, it must amount to a demonstration, and must imply the absolute impossi bility of any contrary supposition. Every effect, then, beside the communication of motion, implies a formal contradiction; and 'tis impossible not only that it can exist, but also that it can be conceived. But we may soon satisfy ourselves of the contrary, by forming a clear and consistent idea of one body's moving upon another, and of its rest immediately upon the contact or of its returning back in the same line in which it came; or of its annihilation, or circular or elliptical motion; and in short, of an infinite number of other changes, which they may suppose it to undergo. These suppositions are all consistent and natural; and the reason why we imagine the communication of motion to be more consistent and natural, not only than those suppositions, but also than any other natural effect, is founded on the relation of resemblance betwixt the cause and effect, which is here united to experience, and binds the objects in the closest and most intimate manner to each other, so as to make us imagine them to be absolutely inseparable. Resemblance, then, has the same or a parallel influence with experience; and |