My manner of thinking, and an objection formerly made, oblige me in the next place to say something concerning the means of knowing what is true: whether there are any that are sure, and which one may safely rely upon. For if there be not, all that I have written is an amusement to no purpose. Besides, as this will lead me to speak of reason, etc., some truths may here (as some did in the former section) fall in our way, which may be profitable upon many occasions; and what has been already asserted, will also be further confirmed.

I. An intelligent being, such as is mentioned before, must have some immediate objects of his understanding, or at least a capacity of having such. For if there be no object of his intellect, he is intelligent of nothing, or not intelligent. And if there are no immediate objects, there can be none at all: because every object must be such (an object) either in itself immediately, or by the intervention of another which is immediate, or of several, one of which must at least be immediate.

II. An intelligent being, among the immediate objects of his mind, may have some that are abstract and general. I shall not at present inquire how he comes by them (it matters not how), since this must be true if there is any such thing as a rational being. For, that reason is something different from the knowledge of particulars may appear from hence: because it is not confined to particular things or cases. What is reason in one instance, is so in another. What is reasonable with respect to Quinctius, is so in respect of Nævius.120 Reason is performed in species. A rational being, therefore, must have some of these species (I mean specific and abstract ideas) to work with, or some superior method, such as perhaps some higher order of reasoners may have but we have not.

The knowledge of a particular idea is only the particular knowledge of that idea or thing: there it ends. But reason is something universal, a kind of general instrument, applicable to particular things and cases as they occur. We reason about particulars, or from them; but not by them.

In fact we find within ourselves many logical, metaphysical, mathematical ideas, no one of which is limited to any particular or individual thing⁠—but they comprehend whole classes and kinds. And it is by the help of these that we reason and demonstrate. So that we know, from within ourselves, that intelligent beings not only may have such abstract ideas as are mentioned in the proposition, but that some actually have them: which is enough for my purpose.

III. Those ideas or objects that are immediate, will be adequately and truly known to that mind whose ideas they are. For ideas can be no further the ideas of any mind, than that mind has (or may have) a perception of them: and therefore that mind must perceive the whole of them, which is to know them adequately.

Again: these ideas being immediate, nothing (by the term) can intervene to increase, diminish, or any way alter them. And to say the mind does not know them truly, implies a contradiction, because it is the same as to say that they are misrepresented: that is, that there are intervening and misrepresenting ideas.

And lastly: there cannot be an immediate perception of that which is not; nor therefore of any immediate object otherwise than as it is. We have indeed many times wrong notions, and misperceptions of things: but then these things are not the immediate objects. They are things, which are notified to us by the help of organs and media, which may be vitiated, or perhaps are defective at best, and incapable of transmitting things as they are in themselves, and therefore occasion imperfect and false images. But then, even in this case, those images and ideas that are immediate to the percipient are perceived as they are: and that is the very reason why the originals, which they should exhibit truly, but do not, are not perceived as they are. In short, I only say the mind must know its own immediate ideas.

IV. What has been said of these ideas which are immediate, may be said also of those relations or respects which any of those ideas bear immediately each to other: they must be known immediately and truly. For if the relation be immediate, the ideas cannot subsist without it; it is of their nature: and therefore they cannot be known adequately, but this must be known too. They are in this respect like the ideas of whole and part. The one cannot be without the other: nor either of them not discover that relation by which the one must be always bigger and the other less.

To say no more, we may satisfy ourselves of the truth of this, as well as of the foregoing propositions, from the experiences of our own minds, where we find many relations that are immediately seen, and of which it is not in our power to doubt.121 We are conscious of a knowledge that consists in the intuition of these relations. Such is the evidence of those truths, which are usually called axioms, and perhaps of some short demonstrations.

V. Those relations or respects which are not immediate, or apparent at the first view, may many times be discovered by intermediate relations, and with equal certainty. If the ratio of B to D does not instantly show itself, yet if the ratio of B to C122 does, and that of C to D,123 from hence the ratio of B to D124 is known also. And if the mean quantities were ever so many, the same thing would follow; provided the reason of every quantity to that which follows next in the series be known. For the truth of this I vouch the mathematicians:125 as I might all, that know any science, for the truth of the proposition in general. For thus theorems and derivative truths are obtained.

VI. If a proposition be true, it is always so, in all the instances and uses to which it is applicable. For otherwise it must be both true and false. Therefore

VII. By the help of truths already known, more may be discovered. For

1. Those inferences, which arise presently from the application of general truths to the particular things and cases contained under them, must be just. E.g. “The whole is bigger than a part”: therefore A (some particular thing) is more than half A. For it is plain that A is contained in the idea of whole, as half A is in that of part. So that if the antecedent proposition be true, the consequent, which is included in it, follows immediately, and must also be true. The former cannot be true unless the other be so too. What agrees to the genus, species, definition, whole, must agree to the species, individuals, thing defined, the part. The existence of an effect infers directly that of a cause; of one correlate that of the other; and so on. And what is said here holds true (by the preceding proposition) not only in respect of axioms and first truths, but also and equally of theorems and other general truths, when they are once known. These may be capable of the like applications; and the truth of such consequences as are made by virtue of them, will always be as evident as that of those theorems themselves.

2. All those conclusions which are derived through mean propositions that are true, and by just inferences, will be as true as those from which they are derived. My meaning is this: every just consequence is founded in some known truth, by virtue of which one thing follows from another, after the manner of steps in an algebraic operation; and if inferences are so founded, and just, the things inferred must be true, if they are made from true premises.

Let this be the form of an argument. M = P: S = M: ergo S = P. Here if S = M be false, nothing is concluded at all: because the middle proposition is in truth not S = M, but perhaps S = Ma, which is foreign to the purpose. If S = M be true, but M = P false, then the conclusion will indeed be a right conclusion from those premises: but they cannot show that S = P, because the first proposition, if it was expressed according to truth, would be Me = P, which is another thing, and has no place in the argument. But if these two propositions are both true, M = P, S = M, then it will not only be rightly concluded, but also true, that S = P. For the second or middle proposition does so connect the other two, by taking in due manner a term from each of them, (or to speak with the logicians, by separately comparing the predicate or major term of the conclusion with the medium in the first proposition, and the subject or minor term with it in the second), that if the first and second are true, the third must be so likewise, all being indeed no more than this: P = M = S. For here the inference is just, by what goes before, being founded in some such truth as this, and resulting immediately from the application of it, Quæ eidem æqualía sunt, et inter se sunt æqualia; or Quæ conveniunt in eodem tertio, etiam inter se conveniunt; or the like.126 Now if an inference thus made is justifiable, another, made after the same manner, when the truth discovered by it is made one of the premises, must be so too; and so must another after that; and so on. And if the last, and all the intermediate inferences, be as right as the first is supposed to be, it is no matter to what length the process is carried. All the parts of it being locked together by truth, the last result is derived through such a succession of mean propositions as render its title to our assent not worse by being long.

Since all the forms of true syllogisms may be proved to conclude rightly, all the advances made in the syllogistic method, toward the discovery or confirmation of truth, are so many instances and proofs of what is here asserted. So also are the performances of the mathematicians. From some self-evident truths and a few easy theorems, which they set out with at first, to what immense lengths, and through what a train of propositions, have they propagated knowledge! How numerous are their theorems and discoveries now, so far once out of human ken!

I do not enter so far into the province of the logician as to take notice of the difference there is between the analytic and synthetic methods of coming at truth or proving it; whether it is better to begin the disquisition from the subject, or from the attribute. If, by the use of proper media, anything can be shown to be or not to be, I care not from what term the demonstration or argument takes its rise. Either way, propositions may beget their like, and more truth be brought into the world.

VIII. That power which any intelligent being has⁠—of surveying his own ideas and comparing them; of forming to himself, out of those that are immediate and abstract, such general and fundamental truths as he can be sure of;127 and of making such inferences and conclusions as are agreeable to them, or to any other truth, after it comes to he known; in order to find out more truth, prove or disprove some assertion, resolve some question, determine what is fit to be done upon occasion, etc., the case or thing under consideration being first fairly stated and prepared⁠—is what I mean by the faculty of reason, or what entitles him to the epithet “rational.” Or in short, Reason is a faculty of making such inferences and conclusions as are mentioned under the preceding proposition, from anything known or given.

The Supreme being has no doubt a direct and perfect intuition of things, with their natures and relations, lying as it were all before Him, and pervious to His eye; or at least we may safely say that He is not obliged to make use of our operose methods by ideas and inferences, but knows things in a manner infinitely above all our conceptions. And as to superior finite natures, what other means of attaining to the knowledge of things they may have is a thing not to be told by me, or how far they may excel us in this way of finding truth. I have an eye here chiefly to our own circumstances. Reason must be understood, when it is ascribed to God, to be the Divine reason; when to other beings above us, to be their reason; and in all of them, to transcend ours as much as their natures respectively do our nature.128

It cannot be amiss to note further, that though a man who truly uses his rational powers⁠—has abstract and universal ideas obtained by reflection; out of these frames to himself general truths, or apprehends the strength of such, and admits them, when they occur to him; by these, as by so many standards, measures and judges of things; and takes care to have the materials which he makes use of in reasoning, to be rivetted and compacted together by them⁠—yet by a habit of reasoning he may come to serve himself of them, and apply them so quick, that he himself shall scarce observe it. Nay, most men seem to reason by virtue of a habit acquired by conversation, practice in business, and examples of others, without knowing what it is that gives the solidity even to their own just reasonings: just as men usually learn rules in arithmetic, govern their accounts by them all their days, and grow very ready and topping in the use of them, without ever knowing or troubling their heads about the demonstration of any one of them. But still though this be so, and men reason without adverting upon general ideas and abstract truths, or even being aware that there are any such⁠—as it were by rule or a kind of rote⁠—yet such there are, and upon them rests the weight of reason as its foundation.

This, by the way, helps us to detect the cause why the generality of people are so little under the dominion of reason: why they sacrifice it to their interests and passions so easily; are so obnoxious to prejudices, the influence of their company, and din of a party; so apt to change, though the case remains the very same; so unable to judge of things that are ever so little out of the way; and so conceited and positive in matters that are doubtful, or perhaps to discerning persons manifestly false. Their reasoning proceeds in that track which they happen to be got into, and out of which they know not one step, but all is to them Terra incognita; being ignorant of the scientific part, and those universal, unalterable principles, upon which true reasoning depends, and to find which and the true use of them are required cool hours and an honest application, beside many preparatives.

In the next place, it must be noted that one may reason truly from that which is only probable, or even false.129 Because just inferences may be made from propositions of these kinds: that is, such inferences may be made as are founded in certain truths, though those propositions themselves are not certainly true. But then what follows or is concluded from thence, will be only probable, or false, according to the quality of that proposition, or those propositions, from which the inference is made.

Again, it should be observed that what I have said of reasoning, chiefly belongs to it as it is an internal operation. When we are to present our reasonings to others, we must transfer our thoughts to them by such ways as we can. The case is to be stated in a manner suitable to their capacities; a fair narration of matters of fact, and their circumstances, to be made; many times persons and things to be described by proper diatyposes and the like: all which are additional labor, and take up much room in discourses and books, and are performed by different authors upon different subjects, and in different kinds of writing, with an infinite variety of methods and forms, according to men’s different views and capacities; and many times not without a necessity of some condescensions, ascititious advantages, and even applications to the passions. But notwithstanding this, in strict reasoning nothing is required but to lay steps in a due order, firmly connected, and expressed properly, without flourish;130 and to arrive at truth by the shortest and clearest gradation we are able.

Once more: perhaps disputacious men may say I ascribe the investigation of truth to one faculty, when it is in reality the joint business of several. For when we go about this work, we are forced to make use of subordinate powers, and even external helps; to draw diagrams and put cases in our own imagination; to correct the images there, compound them, divide them, abstract from them; to turn over our memory, and see what has been entered and remains in that register; even to consult books, and use pen and ink. In short, we assemble all such axioms, theorems, experiments, and observations, as are already known, and appear capable of serving us, or present themselves upon the opening and analysis of the question or case before us. And when the mind has thus made its tour, fetched in materials from every quarter, and set them in its own view, then it contemplates, compares, and methodizes them; gives the first place to this, the second to that, and so on; and when trials do not succeed rightly, rejects some, adopts others, shifts their order, etc., till at last the series is so disposed that the thing required comes up resolved, proved, or disproved, by a just conclusion from proper premises. Now, in this process there seem to be many faculties concerned in these acts of circumspection, recollection, invention, reflection, comparing, methodizing, judging. But what if all this be so? I do not exclude the use of such subservient powers, or other helps as are necessary to the exerting this faculty of reason; nor deny the mind matter to work upon. I may allow all the intellectual faculties their proper offices, and yet make reason to be what I have described it to be.

IX. There is such a thing as right reason, or, Truth may be discovered by reasoning.131 The word “reason” has several acceptations. Sometimes it is used for that power mentioned in the last proposition, as when we say: “Man is a being endowed with reason.” And then the sense of this proposition must be this: that there is such a use to be made of this power, as is right, and will manifest truth. Sometimes it seems to be taken for those general truths, of which the mind possesses itself from the intimate knowledge of its own ideas, and by which it is governed in its inferences and conclusions, as when we say: “Such a thing is agreeable to reason:” for that is as much as to say it is agreeable to the said general truths, and that authentic way of making deductions which is founded in them. And then the sense of this proposition is that there are such general truths, and such a right way of inferring. Again: sometimes it seems to stand only for some particular truth, as it is apprehended by the mind with the causes of it, or the manner of its derivation from other truth: that is, it differs not from truth execept in this one respect, that it is considered not barely in itself, but as the effect and result of a process of reasoning; or it is truth with the arguments for our assent, and its evidences, about it; as when it is said: “that such or such an assertion is reason.” And then the sense of the proposition is that there are truths so to be apprehended by the mind. So all comes to this at last: truth (or there are truths, which) may be discovered, or found to be such, by reasoning.

If it were not so, our rational faculties, the noblest we have, would be vain.

Beside, that it is so appears from the foregoing propositions and what we know within ourselves. ’Tis certain we have immediate and abstract ideas: the relations of these are adequately known to the mind, whose ideas they are; the propositions expressing these relations are evidently known to be true; and these truths must have the common privilege and property of all truths: to be true in all the particulars and uses to which they are applicable. If, then, any things are notified to us by the help of our senses, or present themselves by any other way or means, to which these truths may be immediately applied, or from whence deductions may be made after the forementioned manner, new truths may be thus collected. And since these new truths, and the numerous descendents that may spring from their loins, may be used still in the same manner, and be as it were the seed of more truth, who can tell at what undescried fields of knowledge even men may at length arrive? At least, nobody can doubt but that much truth, and particularly of that kind which is most useful to us in our conduct here, is discoverable by this method.

They, who oppugn the force and certainty of reason, and treat right reason as a chimera, must argue against reason either with reason, or without reason. In the latter way they do nothing; and in the former they betray their own cause, and establish that which they labor to dethrone. To prove there is no such thing as right reason, by any good argument, is indeed impossible: because that would be to show there is such a thing, by the manner of proving that there is not.

And further, if this proposition be not true, there is no right reasoning in Euclid; nor can we be sure that what is there demonstrated is true. But to say this, I am sure, is absurd. Nor do I desire that this proposition, which I here maintain, should be esteemed more certain than those demonstrated by him: and so certain it must be, because there can be no certainty in them, if this be not true.

The great objection against all this is taken from the many instances of false reasoning and ignorance, with which the practices, discourses, writings of mankind are too justly taxed. But, in answer to it, I would have it minded that I do not say men may not, by virtue of their freedom, break off their meditations and inquiries prematurely, before they have taken a sufficient survey of things; that they may not be prepossessed with inveterate errors, biased by interest, or carried violently down with the stream of a sect or fashion, or dazzled by some darling notion or bright name;132 that they may not be unprovided of a competent flock of præcognita and preparative knowledge; that (among other things) they may not be ignorant of the very nature of reasoning, and what it is that gives sinews to an inference, and makes it just; that they may not want philosophy, history, or other learning, requisite to the understanding and stating of the question truly; that they may not have the confidence to pretend to abilities which they have not, and boldly to judge of things as if they were qualified, when they are not; that they may not be impotent in their elocution, and misrepresent their own thoughts, by expressing themselves ill, even when within themselves they reason well; that many understandings may not be naturally gross, good heads often indisposed, and the ablest judges sometimes overseen, through inadvertence or haste⁠—I say none of these things. The contrary, I confess, is manifest: and it is in opposition to those errors, which appear in these cases under the name of reason, that we are forced to add the epithet right, and to say right reason instead of reason only, to distinguish it from that which wrongfully assumes that appellation. Nor, moreover, do I say that by reasoning the truth is to be discovered in every case: that would imply an extent of knowledge which we cannot pretend to. I only say that there is such a thing as right reason, and truth discoverable by it.

I might add that he whose faculties are entire and sound, and who by a proper exercise of his mind in scientific studies first opens and enlarges its capacity, and renders his intellectuals active and penetrating; takes care to furnish himself with such leading truths as may be useful to him, and of which he is assured in his own breast; and in treating any subject keeps them still in his eye, so that his discourse may be agreeable to them: I say, such a one is not in much danger of concluding falsely. He must either determine rightly, or soon find that the subject lies out of his reach. However he will be sensible that there are many things, within his sphere, concerning which he may reason; and that there are truths to be found, by this use of his faculties, in which he may securely acquiesce.

Thus, that question supposed to be asked, “How shall a man know what is true?” is in part answered. More shall be added by and by: only a proposition or two, which ought not to be omitted, must be first inserted.

X. To act according to right reason, and to act according to truth, are in effect the same thing. For in which sense soever the word “reason” is taken, it will stand either for truth itself, or for that which is instrumental in discovering and proving it to be such: and then, with respect to this latter sense, whoever is guided by that faculty, whose office consists in distinguishing and pointing out truth, must be a follower of truth, and act agreeably to it. For to be governed by any faculty or power is to act according to the genuine decisions and dictates of it.

That reason which is right (by the meaning of the words) must conclude rightly: but this it cannot do if the conclusion is not true, or truth.

That is (for so I would be understood), if the principles and premises from whence it results are true,133 and certainly known to be so, the conclusion may be taken as certain and absolute truth; but otherwise the truth obtained at the end of the argument is but hypothetical, or only this: that such a thing is so, if such another, or such others are so or so.

XI. To be governed by reason is the general law imposed by the Author of nature134 upon them whose uppermost faculty is reason; as the dictates of it, in particular cases, are the particular laws to which they are subject. As there are beings which have not so much as sense, and others that have no faculty above it; so there may be some who are endowed with reason, but have nothing higher than that. It is sufficient, at present, to suppose there may be such. And then if reason be the uppermost faculty, it has a right to control the rest by being such. As, in sensitive animals, sense commands gravitation and mechanical motions in those instances for which their senses are given, and carries them out into spontaneous acts: so, in rational animals, the gradation requires that reason should command sense.

It is plain that reason is of a commanding nature:135 it enjoins this, condemns that, only allows some other things, and will be paramount (in an old word, τὸ ἡγεμόνικὸν136) if it is at all. Now, a being who has such a determining and governing power, so placed in his nature as to be essential to him, is a being certainly framed to be governed by that power. It seems to be as much designed by nature, or rather the Author of nature, that rational animals should use their reason, and steer by it, as it is by the shipwright that the pilot should direct the vessel by the use of the rudder he has fitted to it. The rudder would not be there if it was not to be used; nor would reason be implanted in any nature only to be not cultivated and neglected. And it is certain it cannot be used, but it must command: such is its nature.

It is not in one’s power deliberately to resolve not to be governed by reason. For (here, the same way of arguing may be used that was lately) if he could do this, he must either have some reason for making that resolution, or none. If he has none, it is a resolution that stands upon no foundation, and therefore in course falls: and if he has some reason for it, he is governed by reason. This demonstrates that reason must govern.

XII. If a rational being, as such, is under an obligation to obey reason, and this obedience, or practice of reason, coincides with the observation of truth, these things plainly follow:

1. That what is said in section I, proposition IV must be true with respect to such a being for this further cause: because, to him, nothing can be right that interferes with reason, and nothing can interfere with truth but it must interfere with reason. Such a harmony there is between them. For whatever is known to be true, reason either finds it, or allows it, to be such. Nothing can be taken for true by a rational being, if he has a reason to the contrary.

2. That there is to a rational being such a thing as religion, which may also, upon this further account, properly be called natural. For certainly to obey the law which the Author of his being has given him, is religion; and to obey the law which He has given, or revealed to him by making it to result from the right use of his own natural faculties, must be to him his natural religion.

3. A careful observation of truth, the way to happiness, and the practice of reason are in the issue the same thing. For, of the two last, each falls in with the first, and therefore each with other. And so, at last, natural religion is grounded upon this triple and strict alliance, or union, of truth, happiness, and reason, all in the same interest, and conspiring by the same methods, to advance and perfect human nature; and its truest definition is: “The pursuit of happiness by the practice of reason and truth.”

Permit me here again to insert an observation obiter.

Observation: The κριτήριον137 of right reason and truth, or that which is to be regarded in judging of right and truth, is private; that is: everyone must judge for himself. For since all reasoning is founded originally in the knowledge of one’s own private ideas, by virtue of which he becomes conscious of some first truths that are undeniable; by which he governs his steps in his pursuits after more truths, etc.; the criterion, or that by which he tries his own reasonings and knows them to be right, must be the internal evidence he has already of certain truths, and the agreeableness of his inferences to them. One man can no more discern the objects of his own understanding, and their relations, by the faculties of another, than he can see with another man’s eyes, or one ship can be guided by the helm of another. They must be his own faculties and conscience that must determine him. Therefore, to demand another man’s assent to anything, without conveying into his mind such reasons as may produce a sense of the truth of it, is to erect a tyranny over his understanding and to demand a tribute which it is not possible for him to pay.138 It is true, indeed, though I cannot see with another man’s eyes, yet I may be assisted by another who has better eyes, in finding an object and the circumstances of it; and so men may be assisted in making their judgments of things. They may be informed of things which they did not know before, and which yet require a place among those that are to be considered; and they may be directed what to advert principally upon, how to state the question, how to methodize their thoughts, and in general how to reason: especially if they want learning, or have only that part of it which is little conversant in close reflections, and does not teach them to reason, or (as the case too often is) teaches them not to reason. But still this is all in order to produce such a light in them, that by it they may see and judge for themselves. An opinion, though ever so true and certain to one man, canot be transfused into another as true and certain by any other way but by opening his understanding, and assisting him so to order his conception that he may find the reasonableness of it within himself.

To prevent mistakes, I pray take notice here that, though I say men must judge for themselves, I do not say they must in all cases act according to their private and single judgments. In respect of such things as are private, and concern themselves only, or such as are left open and subject to every man’s own sense, they may and ought, only preserving a due deference to them who differ from them, and are known upon other occasions to have more knowledge and literature than themselves; but when a society is concerned, and has determined anything, it may be considered as one person of which he, who dissents from the rest, is only perhaps a small particle; and then his judgment will be in a manner absorbed and drowned in that of the majority, or of them to whom the power of judging is entrusted. But I must not digress too far from the main business, the ways of coming at truth.

XIII. The reports of sense are not of equal authority with the clear demonstrations of reason, when they happen to differ. It is true, the ideas caused by the impression of sensible objects are real ideas, and truly known to the mind as they are in themselves; and the mind may use them, and reason truly upon them: that is, the mind may make a right use of the ideas which it finds in itself. But then, whether these are the true ectypes of their originals, and drawn to the life, is many times a question⁠—and many times it is evident they are not. For that which has been anticipated under proposition III, but properly belongs to this, must be acknowledged. They are conveyed through media and by instruments susceptive of different dispositions and alterations, and may consequently produce different representations; and these cannot all be right. But suppose those instruments and media to be as entire and pure as when entirest and purest; yet still there may be, in many respects, an incapacity in the faculty to notify things just as they are. How mightily are the shape and size of a visible object varied upon us according to its distance, and the situation of the place from whence the prospect is taken? Now, these things cannot be said of the reports, or rather determinations, of reason. For in pure reasoning we use our own ideas for themselves, and such as the mind knows them to be, not as representatives of things that may be falsely exhibited. This internal reasoning may indeed be wrongly applied to external things, if we reason about them as being what they are not; but then this is the fault not of reason, but of sense, which reports the case wrong, or perhaps of the person, who has not been sufficiently industrious to inform himself.

The same familiar instance of vision proves further, that reason may be applied to overrule and correct sense. For when the pictures of objects are pricked out by the pencils of rays upon the retina of the eye, and do not give the true figure of those objects (as they not always do, being diversely projected, as the lines proceeding from the several points happen to fall upon that concave surface); this, though it might impose upon a being that has no faculty superior to sense, does not impose upon our reason, which knows how the appearance is altered, and why. To think the sun139 is not bigger than it appears to the eye to be,140 seems to be the last degree of stupidity. He must be a brute (so far from being a philosopher), who does not know that the same line (e.g. the diameter of the sun) at different distances subtends different angles at the eye. A small matter of reason may serve to confute sense in this and the like cases.

Objection: How can reason be more certain than sense, since reason is founded in abstractions which are originally taken from sensible objects? Answer: Perhaps the mind may, by being exercised at first about particular objects, by degrees find in itself this capacity of considering things by their species, making abstractions, etc. which it would not have done, had it never known any of these particulars. But then, after it has found this capacity in itself, and attained to the knowledge of abstract and general ideas, I do not see why this capacity of reasoning by the help of them may not be tried, upon this proficience, to censure and correct the advices of sense concerning even such particulars as first gave occasion to the mind to exert this capacity and raise itself. Is it a new thing for a scholar, to make such a progress in learning as to be able afterward to teach the master, from whom he received his first rudiments? May not the modern philosophers correct the ancients, because these first showed them the way, and led them into the study of nature? If we look impartially into the history of learning, and even of religion, we shall find that truth has generally advanced by degrees, and many times (very many; as if that was the method of introducing knowledge among men) risen out of fable and error, which gave occasion to those inquiries by which themselves were detected. Thus, blind ignorance was succeeded by a twilight of sense; this brightend by degrees; at last the sun, as it were, rose upon some parts of the commonwealth of learning, and cleared up many things; and I believe many more will in time be cleared, which, whatever men think, are yet in their dark and uncultivated state. The understanding, though it starts from particulars, in time makes a further progress, taking in generals, and such notions logical, metaphysical, etc., as never could possibly come in by the senses.141 Besides, further, the capacity itself, of admitting and considering general ideas, was originally in the mind, and is not derived from without. The intelligences communicated by sense are only an occasion of using what it had before.142 Just as a master may, by the exercises he sets, excite the superior capacity of his scholar.

In a word: no man does, or can pretend to, believe his senses when he has a reason against it, which is an irrefragable proof that reason is above sense and controls it. But,

XIV. The reports of sense may be taken for true, when there is no reason against it.143 Because when there is no reason not to believe, that alone is a reason for believing them. And therefore,

XV. In this case, to act according to them (i.e. as taking the informations of sense to be true) is to act according to reason and the great law of our nature.

Thus, it appears that there are two ways by which we may assure ourselves of the truth of many things,144 or at least may attain such a degree of certainty as will be sufficient to determine our practice: by reason, and by sense under the government of reason, that is, when reason supports it, or at least does not oppose it. By the former, we discover speculative truths; by the latter, or both together, matters of fact.

XVI. Where certainty is not to be had,145 probability must be substituted into the place of it: that is, it must be considered, which side of the question is the more probable.

Probability, or that which in this case may incline one to believe any proposition to be true rather than false, or anything to be rather than not to be, or the contrary, will generally show itself upon the application of these and suchlike rules:

1. That may be reckoned probable, which, in the estimation of reason, appears to be more agreeable to the constitution of nature. Nobody can certainly foretell that sice-ace will come up upon two dies fairly thrown before ambs-ace: yet anyone would choose to lay the former, because in nature there are twice as many chances for that as for the other. If a strolling wolf should light upon a lamb, it is not evidently known that he will tear the lamb, but there is such a natural propension in that kind to do it, that nobody would much question the event. (This instance might have been taken from amongst men, who are generally, as far as they can be, wolves one to another.) If a parent causes his child to be instructed in the foundations of useful learning, educates him virtuously, and gives him his first impulse and direction in the way to true happiness, he will be more likely to proceed and continue in it, than he would be to hit upon it, and continue in it too, if he was left to himself to be carried away by his own passions, or the influence of those people into whose hands he might fall, the bias of the former lying towards vice, and misery in the end, and the plurality of the latter being either wicked or ignorant or both. So that the advantage, in point of probability, is on the side of good education.146 When Herodotus writes that the Egyptian priests reported the sun had, within the compass of 11,340 years, twice risen where it now sets and set where it rises,147 what is fit to be believed concerning the truth of this relation (as of many others) is easily discernable by this rule. Herodotus, possibly delighting in teratical stories, might tell what he never heard; or the passage may be an interpolation; or it may be altered in transcribing; or the priests, who pretended much to a knowledge of great antiquities, might, out of mere vanity, to show what children the Greeks were in respect of them, invent such a monstrous relation, and impose it upon them whom they thought to have not much science among them; or it might be got into their memoirs before their time, who related it to Herodotus, and so pass upon posterity, as many other fictions and legends have done. These are such things as are well known to have happened often. But, that the diurnal rotation of the earth about her axis should be inverted is a phenomenon that has never been known to happen by anybody else, either before or since; that is favored by no observation; and that cannot be without great alteration in the mundane system, or those laws by which the motions of the planets, and of our earth among the rest, are governed. That this account, then, may be false is very consistent with the humor and circumstances of mankind: but that it should be true is very inconsistent with those laws by which the motions of the celestial bodies seem to be regulated, and tend to persevere in their present courses and directions. It is therefore in nature much more probable that this account is false. The odds are on that side.

2. When any observation has hitherto constantly held true, or most commonly proved to be so, it has by this acquired an established credit; the cause may be presumed to retain its former force, and the effect may be taken as probable, if in the case before us there does not appear something particular: some reason for exception. No man can demonstrate that the sun will rise again, yet everyone does, and must, act as if that was certain:148 because we apprehend no decay in the causes which bring about this appearance, nor have any other reason to mistrust the event, or think it will be otherwise a few hours hence than it has been hitherto. There is no apodictical argument to prove that any particular man will die: but yet, he must be more than mad who can presume upon immortality here, when he finds so many generations all gone, to a man, and the same enemies that have laid them prostrate still pursuing their victories. These, and suchlike, though in strictness perhaps not certainties, are justly current for such: so great is their probability. There are other observations which, though not so infallible as those, deserve yet to be thought of, and to have a share in the direction of our judgments. E.g. There have been men in the world, and no doubt still are, who, having had opportunities of imposing falsities upon mankind, of cheating, or committing other wickedness, have yet in spite of temptation preserved their integrity and virtue: but, since opportunity has so seldom failed to corrupt them who have been in possession of her, and men’s interests and passions continue in general the same, it is more probable her charms will still have the same power and effect which they used to have; which whoever does not mind, will be woefully obnoxious to be abused by frauds pious and impious.149 Briefly: when there is no particular reason for the contrary, what has oftenest happened may, from experience, most reasonably be expected to happen again.

3. When neither nature nor other observations point out the probable conjecture to us, we must be determined (if it be necessary for us to be determined at all) by the reports, and sense of them, whom we apprehend, judging with the best skill we have,150 to be most knowing151 and honest.152 Of all these rules, the first is that which deserves the principal regard; the other two are of use, when nature so utterly excludes us from her bosom that no opportunity is allowed of making a judgment.

4. Lastly: when nature, the frequent repetition of the same event, and the opinion of the best judges concur to make anything probable, it is so in the highest degree.

It appears, from what has been said concerning the nature and foundations of probability, that the force of it results from observation and reason together. For here, the one is not sufficient without the other. Reason without observation wants matter to work upon; and observations are neither to be made justly by ourselves, nor to be rightly chosen out of those made by others, nor to be aptly applied, without the assistance of reason. Both together may support opinion and practice in the absence of knowledge and certainty. For, those observations upon the nature of men and things which we have made ourselves, we know; and our own reasoning concerning them, and deductions from them, we know; and from hence, there cannot but arise in many cases an internal obligation to give our assent to this rather than that, or to act one way rather than another. And, as to the observations of others, they may be so cautiously and skillfully selected, as to become almost our own; since our own reason and experience may direct us in the choice and use of them. The remarks and advice of old men,153 who have gone through variety of scenes, lived long enough to see the consequences of their own and other people’s actings, and can now with freedom154 look back and tell where they erred, are ordinarily sure to be preferred to those of young and raw actors. The gnomæ, apologues, etc. of wise men, and such as have made it their business to be useful spies upon nature and mankind, national proverbs, and the like,155 may be taken as maxims commonly true. Men in their several professions and arts, in which they have been educated, and exercised themselves all their days, must be supposed to have greater knowledge and experience than others can usually have; and therefore, if through want of capacity or honesty they do not either lose or belie their opportunities and experience, they are, in respect of those things to which they have been bred and inured, more to be relied upon. And, lastly, histories written by credible and industrious authors, and read with judgment, may supply us with examples, parallel cases, and general remarks, profitable in forming our manners and opinions too. And by the frequent perusal of them, and meditation upon them, a dexterity in judging of dubious cases is acquired. Much of the temper of mankind, much of the nature and drift of their counsels, much of the course of Divine providence, is visible in them.

To conclude: that we ought to follow probability, when certainty leaves us, is plain, because then it becomes the only light and guide we have. For unless it is better to wander, and fluctuate in absolute uncertainty, than to follow such a guide⁠—unless it be reasonable to put out our candle because we have not the light of the sun⁠—it must be reasonable to direct our steps by probability, when we have nothing clearer to walk by. And if it be reasonable, we are obliged to do it by proposition XI. When there is nothing above probability, it does govern; when there is nothing in the opposite scale, or nothing of equal weight, this, in the course of nature, must turn the beam. Though a man, to resume the instance before, cannot demonstrate that sice-ace will come up before ambs-ace, he would find himself obliged (if he could be obliged to lay at all) to lay on that side; nor could he not choose to do it. Though he would not be certain of the chance, he would be certain of his own obligation, and on which side it lay.

Here, then, is another way of discovering, if not truth, yet what in practice may be supposed to be truth. That is, we may by this way discover whether such propositions as these be true: “I ought to do this, rather than that” or, “to think so, rather than the contrary.”

Observation: I have done, now, what I chiefly intended here. But, over and above that, we may almost from the premises collect,

First, the principal causes of error, which I take to be such as these:

1. Want of faculties; when men pretend to judge of things above them. As some (straying out of their proper element and falling into the dark, where they find no ideas but their own dreams, come to) assert what they have no reason to assert, so others deny what there is the highest reason to believe, only because they cannot comprehend it.

2. Want of due reflection upon those ideas we have, or may have: by which it comes to pass that men are destitute of that knowledge which is gained by the contemplation of them, and their relations; misapply names, confusedly; and sometimes deal in a set of words and phrases to which no ideas at all belong, and which have indeed no meaning. Of kin to this is,

3. Want of proper qualifications and προπαιδεύματα.156 As when illiterate people invade the provinces of scholars; the half-lettered are forward, and arrogate to themselves what a modest, studious man dares not,157 though he knows more; and scholars that have confined themselves to one sort of literature, launch out into another: unsuccessfully all.

4. Not understanding in what the nature and force of a just consequence consists. Nothing more common than to hear people assert that such a thing follows from such a thing, when it does not follow: i.e., when such a consequence is founded in no axiom, no theorem, no truth that we know of.

5. Defects of memory and imagination. For men, in reasoning, make much use of these: memory is upon many occasions consulted, and sometimes drafts made upon the fantasy. If, then, they depend upon these, and these happen to be weak, clouded, perverted any way, things may be misrepresented, and men led out of the way by misshapen apparitions. There ought to be, therefore, a little distrust of these faculties, and such proper helps ought to be used, as perhaps the best judgments want the most.

6. Attributing too much to sense. For, as necessary as our senses are to us, there are certainly many things which fall not within their notice; many which cannot be exhibited after the manner of sensible objects, and to which no images belong. Everyone who has but just saluted the mathematics and philosophy, must be convinced that there are many things in nature which seem absurd to sense, and yet must be admitted.

7. Want of refinement, and the practice of thinking and reasoning by ourselves.158 A rambling and irregular life must be attended with a loose and irregular head, ill-connected notions, and fortuitous conclusions. Truth is the offspring of silence, unbroken meditations, and thoughts often revised and corrected.

8. The strength of appetites, passions, prejudices. For by these the understanding may be corrupted, or overborne; or at least the operations of the mind must be much obstructed by the intrusion of such solicitors as are no retainers to the rational powers, and yet strong, and turbulent. Among other prejudices, there is one of a particular nature which you must have observed to be one of the greatest causes of modern irreligion. While some opinions and rites are carried to such an immoderate height as exposes the absurdity of them to the view of almost everybody, but them who raise them, not only gentlemen of the belles lettres, but even men of common sense many times see through them; and then out of indignation and an excessive renitence, not separating that which is true from that which is false, they come to deny both, and fall back into the contrary extreme, a contempt of all religion in general.159

9. Ill stating of a question; when men either put it wrong themselves, or accept it so put from others. A small addition or falsity, slipped into the case, will ferment, and spread itself; an artificial color may deceive one; an encumbered manner may perplex one. The question ought to be presented before its judge clean, and in its natural state, without disguise or distortion. To this last may be subjoined another cause, nearly allied to it: not fixing the sense of terms, and (which must often follow) not rightly understanding what it is that is to be examined and resolved.

Secondly, the reason why the many are commonly in the wrong and so wretchedly misjudge things: The generality of people are not sufficiently prepared, by a proper education, to find truth by reasoning. And, of them who have liberal education, some are soon immersed and lost in pleasures, or at least in fashionable methods of living, rolling from one visit or company to another,160 and flying from nothing so much as from themselves and the quiet retreats proper for meditation and reasoning; others become involved in business and the intricate affairs of life, which demand their attention and engross their time; others fall into a slothful neglect of their studies and disuse of what they have learnt, or want help and means to proceed, or only design to deceive life and gratify themselves with the amusements and sensual parts of learning; and others there are, whose misfortune it is to begin wrong, to begin with the conclusion, taking their opinions from places where they have been bred, or accommodating them to their situation in the world, and the conditions of that employment by which they are to get their bread, before they have ever considered them, and then making the subsequent business of their lives to dispute for them and maintain them, right or wrong. If such men happen to be in the right, it is luck, and part of their portion, not the effect of their improvements; and if they happen to be in the wrong, the more they study, and the more learning they get, the more they are confirmed in their errors, and having set out with their backs upon truth, the further they go, the more they recede from it. Their knowledge is a kind of negative quantity, so much worse or less than no knowledge. Of this sort there are many, and very few indeed (with respect to the bulk of mankind) whose determinations and tenets were ever in the form of questions; there could not otherwise be so many sects and different denominations of men as there are upon the face of the earth. The sum of all, in a few words, is this: many qualifications are requisite in order to judge of some truths, and particularly those which are of greatest importance: proper learning and penetration, vacancy from business, a detachment from the interest of all parties, much sincerity and a perfect resignation to the government of reason and force of truth; which are things not to be reconciled with the usual ignorance, passions, tumultuary lives, and other circumstances which carry most men transverse.