It can feign a train of events, with all the appearance of reality, ascribe to them a particular time and place, conceive them as existent, and paint them out to itself with every circumstance, that belongs to any historical fact, which it believes with the greatest certainty. The degree and direction of every motion is, by the laws of nature, prescribed with such exactness that a living creature may as soon arise from the shock of two bodies as motion in any other degree or direction than what is actually produced by it. Provided we agree about the thing, it is needless to dispute about the terms. I shall only infer from these practices, and this reasoning, that the effect of resemblance in enlivening the ideas is very common; and as in every case a resemblance and a present impression must concur, we are abundantly supplied with experiments to prove the reality of the foregoing principle. Whatever definition we may give of liberty, we should be careful to observe two requisite circumstances; First, that it be consistent with plain matter of fact; secondly, that it be consistent with itself. For as the mind has authority over all its ideas, it could voluntarily annex this particular idea to any fiction, and consequently be able to believe whatever it pleases; contrary to what we find by daily experience. Secondly, It is impossible, that this inference of the animal can be founded on any process of argument or reasoning, by which he concludes, that like events must follow like objects, and that the course of nature will always be regular in its operations.
When any natural object or event is presented, it is impossible for us, by any sagacity or penetration, to discover, or even conjecture, without experience, what event will result from it, or to carry our foresight beyond that object which is immediately present to the memory and senses. From a body of like colour and consistence with bread we expect like nourishment and support. Bereave matter of all its intelligible qualities, both primary and secondary, you in a manner annihilate it, and leave only a certain unknown, inexplicable something, as the cause of our perceptions; a notion so imperfect, that no sceptic will think it worth while to contend against it. Hume is both pretentious and self-indulgent. When a new object, endowed with similar sensible qualities, is produced, we expect similar powers and forces, and look for a like effect. To endeavour, therefore, the proof of this last supposition by probable arguments, or arguments regarding existence, must be evidently going in a circle, and taking that for granted, which is the very point in question.
The academics always talk of doubt and suspense of judgment, of danger in hasty determinations, of confining to very narrow bounds the enquiries of the understanding, and of renouncing all speculations which lie not within the limits of common life and practice. Let us, therefore, use a little freedom, and call them Impressions; employing that word in a sense somewhat different from the usual. You admire, says my friend, as the singular good fortune of philosophy, what seems to result from the natural course of things, and to be unavoidable in every age and nation. But if we still carry on our sifting humor, and ask, What is the foundation of all conclusions from experience? For so long, I presume, will the accounts of miracles and prodigies be found in all history, sacred and profane. First, if the number of witnesses of the miracle be greater than the number of witnesses of the operation of the law, and secondly, if a witness be 100% reliable for then no amount of contrary testimony will be enough to outweigh that person's account. Recall the transition set out in 125 above. The only method of undeceiving us is to mount up higher; to examine the narrow extent of science when applied to material causes; and to convince ourselves that all we know of them is the constant conjunction and inference above mentioned.
To endeavour, therefore, the proof of this last supposition by probable arguments, or arguments regarding experience, must be evidently going in a circle, and taking that for granted, which is the very point in question. Our idea, therefore, of necessity and causation arises entirely from the uniformity observable in the operations of nature, where similar objects are constantly conjoined together, and the mind is determined by custom to infer the one from the appearance of the other. In all cases, we must balance the opposite experiments, where they are opposite, and deduct the smaller number from the greater, in order to know the exact force of the superior evidence. This idea, then, is an idea of reflection, since it arises from reflecting on the operations of our own mind, and on the command which is exercised by will, both over the organs of the body and faculties of the soul. Nothing so like as eggs; yet no one, on account of this appearing similarity, expects the same taste and relish in all of them. The central themes of the book are that very little of what we think we know can actually be derived from any idea that there are actual necessary connections between observed phenomena. It develops an account of human mental functioning which emphasizes the limits of human knowledge and the extent of our reliance on mental habits.
Not to mention, that, to a young beginner, the general observations and maxims occur not always on the proper occasions, nor can be immediately applied with due calmness and distinction. Let us allow that the sentiment of belief is nothing but a conception more intense than what attends mere fictions and arises from customary conjunction of objects. Nothing is counted as a miracle if it ever happens in the common course of nature. Hume brings to bear three important distinctions. This, once again, shows the ignorance of atheists and their tendency to cherry pick sources. Matters of fact, which are the second objects of human reason, are not ascertained in the same manner; nor is our evidence of their truth, however great, of a like nature with the foregoing.
The hearing of an articulate voice and rational discourse in the dark assures us of the presence of some person: Why? That the square of the hypotenuse is equal to the square of the two sides, is a proposition which expresses a relation between these figures. It being a general maxim, that no objects have any discoverable connexion together, and that all the inferences, which we can draw from one to another, are founded merely on our experience of their constant and regular conjunction; it is evident, that we ought not to make an exception to this maxim in favour of human testimony, whose connexion with any event seems, in itself, as little necessary as any other. An act of volition produces motion in our limbs, or raises a new idea in our imagination. It appears that, in single instances of the operation of bodies, we never can, by our utmost scrutiny, discover any thing but one event following another, without being able to comprehend any force or power by which the cause operates, or any connexion between it and its supposed effect. The mutual dependence of men is so great in all societies that scarce any human action is entirely complete in itself, or is performed without some reference to the actions of others, which are requisite to make it answer fully the intention of the agent. The Enquiry has, contrary to its author's expressed wishes, long lived in the shadow of its predecessor, A Treatise of Human Nature. But the same truth may not appear, at first sight, to have the same evidence with regard to events, which have become familiar to us from our first appearance in the world, which bear a close analogy to the whole course of nature, and which are supposed to depend on the simple qualities of objects, without any secret structure of parts.
Thus, it is a law of motion, discovered by experience, that the moment or force of any body in motion is in the compound ratio or proportion of its solid contents and its velocity; and consequently, that a small force may remove the greatest obstacle or raise the greatest weight, if, by any contrivance or machinery, we can increase the velocity of that force, so as to make it an overmatch for its antagonist. But is this a sufficient reason, why philosophers should desist from such researches, and leave superstition still in possession of her retreat? He believed that animals were able to infer the relation between cause and effect in the same way that humans do: through learned expectations. We say, for instance, that the vibration of this string is the cause of this particular sound. Greater good produced by this Being must still prove a greater degree of goodness: a more impartial distribution of rewards and punishments must proceed from a greater regard to justice and equity. But you must confess that the inference is not intuitive; neither is it demonstrative: Of what nature is it, then? It follows, therefore, that the difference between fiction and belief lies in some sentiment or feeling, which is annexed to the latter, not to the former, and which depends not on the will, nor can be commanded at pleasure.
When it is asked, What is the nature of all our reasonings concerning matter of fact? We may observe a like distinction to run through all the other perceptions of the mind. May not both these balls remain at absolute rest? May not both these balls remain at absolute rest? And in all, I highly recommend Hume, to believers and nonbelievers alike. This form of reasoning may seem trivial and obvious; but it may afford matter for curious speculation. The ignorance and inexperience of the young are here plainly distinguishable from the cunning and sagacity of the old, who have learned, by long observation, to avoid what hurt them, and to pursue what gave ease or pleasure. In all cases, we must balance the opposite experiments, where they are opposite, and deduct the smaller number from the greater, in order to know the exact force of the superior evidence. We learn thence the great force of custom and education, which mould the human mind from its infancy and form it into a fixed and established character. Fourth, since every religion claims the veracity of its own miracles as against the miracles of every other religion, the evidence of all other religions opposes the evidence in favor of a miracle in any one particular religion.