An Introduction to the Study of Moral Evidence, ... with an appendix on debating for victory and not for truth

Introduction

TO THE STUDY OF MORAL EVIDENCE; OB, OF THAT SPECIES OF REASONING Wlllin RELATES TO MATTERS OF FACT AND PRACTICE. wrrn an APPENDIX, ON DEBATING FOR VICTORY, AND NOT FOR TRUTH. BY JAMES EDWARD GAMBIER, MA. RECTOR OF LANGLEY, KENT; OF ST. MARY-LE-STRAND, WESTMINSTER AND CHAPLAIN TO THE RIGHT HON. LORD BARHAM. THIRD EDITION ENLARGED. LONDON : PRINTED FOR C. & J. RIVINGTON, st. paul's church-yard, AND WATERLOO-PLACE, FALL-MALL. 1824. LONDON: PRINTED BY R. GILBERT, ST. JOHN'S SQUARE.

Preface

TO THE FIRST EDITION. To form a habit of reasoning justly, is one of the most important objects of education. Much has been done to promote this object by writers on logic, and on the human understanding. Their writings, however, relate principally to reasoning on subjects of pure science, and abstract truths, or the necessary relations of ideas. Little, comparatively, has been written, to teach us how to reason on practical subjects, and the ordinary concerns of life ; but that little is highly valuable. Mr. Locke, in his Essay on the Human Understanding, has treated briefly on probability ; and the author of the Port Royal Art of Thinking, has, at the latter end of his work, introduced two or three chapters on the application of reason'to the events of human life. Both of these writers furnish useful obsera

PREFACE.

. vations on these subjects. Dr. Watts, in the second part of his Treatise on Logic, and his book on the Improvement of the Mind, has laid down many important rules to direct the judg ment on practical questions. In the Encyclo pædia Britannica, also, under the head of meta physics, there are some just remarks on the theory of observation, and testimony. And, Dr. Campbell, in his Philosophy of Rhetoric, has explained at considerable length, the theory of moral evidence. Were young men willing to take the pains of collecting from these, and other authors, all that they could meet with on the subject of moral evidence, they might perhaps, form for them selves, a system sufficient to answer every de sirable purpose. But this is scarcely to be ex pected. For, in the course of education, the principal use of reason is in subjects purely scientific.

It is not, therefore, surprising that students should bestow their chief attention upon that use of it, and neglect, to a great degree, all those principles and rules of argumentation, which they have at that time no occasion to

PREFACE.

. V apply. Hence, it may naturally be expected, that, however well qualified they may be to argue on scientific subjects, they should be in capable of reasoning justly on human events. When their education is finished, it is scarcely to be supposed, that they would recur to those books, which they had formerly studied, to col lect from them such information as they had hitherto neglected ; but which they would now find of the greatest use in the conduct of life. Probably, very few men take this trouble ; and this is one cause, why so few reason correctly on questions which admit of no higher evidence than probability. It is, however, obvious, that that use of rea son, which teaches us how to regulate our judg ments, expectations, and conduct, must be much more important than that, which relates only to science.

And indeed, it is only to the very few out of the whole of mankind, who are engaged in the education of youth, or in pure scientific researches, that the latter can be of any con siderable use, after they have once attained to manhood : but the former is absolutely neces-

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. VI sary to every individual of the human race throughout the whole of his life. Of course, it ought to be studied with greater attention. But, this it probably never will be, unless it be studied professedly, as a separate system. It may be thought, perhaps, that a man, who has formed a habit of reasoning justly on scien tific subjects, will be capable of applying that habit to matters of probability, without studying any system of moral evidence. That the study and practice of demonstrative reasoning will be found of great use towards acquiring skill in moral evidence, is true. It is not meant, there fore, to discourage an application either to logic or to mathematics. On the contrary, an appli cation to both, is strongly recommended, as the best possible means of acquiring an ability of thinking closely and correctly, and of reasoning conclusively.

But then, it is true also, that this study will rarely be found sufficient to enable a man to reason justly on probable subjects ; both because the principles in demonstrative and moral reasoning differ much ; and, because the mind that has been accustomed to yield its as-

PREFACE.

. VII sent to demonstration only, generally finds great difficulty in being satisfied with a lower species of evidence. Hence arises that tendency to scepticism, which has been imputed to the study of mathematics. And, hence it is, that the transition even from pure to mixed mathematics, is often attended with a want of that satisfac tion, which had hitherto been enjoyed. Both these are occasioned by not considering, that different subjects admit of different kinds of evidence ; and by the mind's not being accustomed to yield its assent to that kind of evidence, of which the subject admits. He, who has not attained the knowledge, and accustomed himself to the use of correct and fixed principles of decision on the weight of evidence for matters of fact, must engage in the investigation of many important questions, such, for instance, as the truth of Christianity, with great disadvantage.

The principles, on which he will be required to decide, being new to him, will probably seem to him to have been framed merely for the occasion, and will therefore ap pear to be suspicious. But had he pursued this

PREFACE.

. study with due attention, these principles would have been familiar to him ; he would have been accustomed to apply them to various subjects, and to see that they lead to correct conclusions. To him, therefore, they would afford both a safe and satisfactory ground of decision on the question proposed. This study will, also, be a means of preservation from many errors in the ordinary occurrences of life. Few practical questions call for our decision, on which we are not previously interested on the one side, or the other. The having to search for our principles of judgment, while under the influence of interest, must be an inlet to delusion, in addition to the danger of misapplying them. But, if we have been accustomed to the use of certain fixed principles of evidence, they will naturally present themselves to our minds, when occasions for their application arise ; nor shall we be able to decide inconsistently with them, without being conscious of doing wrong. It would, therefore, be useful to acquire a knowledge of the principles of moral evidence, as well as of those of demonstra-

PREFACE.

. IX tion ; and, perhaps, to pursue the study of these different kinds of evidence at the same time. The Author's motive for engaging in the discussion of this subject, was, his having observed persons of ability and education delude themselves as to the truth of facts, of importance to their moral conduct, by applying to them principles of reasoning, unsuited to the nature of the case. With the principles of demonstrative reasoning, they were well acquainted ; but of those of moral evidence they had not a sufficiently clear and settled knowledge, to put them on their guard against the delusions of inclination or interest in themselves, or the sophistry of others. Hence, even their knowledge of morality, and the general rectitude of their intentions, became of little avail to direct their conduct; for, an error in the fact, is often as fatal to virtue, as an error in the principles of morality.

As there is no book written, professedly, on this subject*, (at least so far as the Author of * " We seem to be very deficient in the logic of probability." Leland's View of Deistical Writers. The expression, Logic

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. X this Tract can learn,) these hints are offered ; but not as new thoughts. For, in the present advanced state of science, little that is new, can be expected on a subject of this nature. Nor are they proposed, as comprising a com plete system, but merely as an introduction to the study of moral evidence. To the learned reader, if any such should honour this Tract with a perusal, an apology may be necessary for the discussion of subjects, which may appear too obvious to need expla nation or proof. But, it should be observed, that this work is intended for the use of those who are only beginners in the science of moral reasoning ; and that, for their information, it was necessary to explain, and prove, even such points as would be perfectly obvious to the more experienced reasoner. This appeared to of Probability, would perhaps convey to many persons a clearer idea of the subject of this Tract, than that which forms its present title.

But the author did not meet with this expression till long after the publication of the second edition ; and it was thought unadvisable to change the title, when the book had already gone through two editions.

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. XI be the more requisite, because, however ob vious those points may be, many of them are too frequently neglected in practice, and that, by persons whose character gives great weight to their example. Hence, it was desirable, that the beginner should be furnished with a weight of proof, calculated to counterbalance such authority. To most readers, it will be necessary to apologise for the dryness of the book. Some thing of this must be attributed to the nature of its subject; for a treatise on the principles of reasoning, can scarcely be otherwise than dry. Yet, some of the blame may, perhaps, be due to the Author, for not having inter spersed his work with a greater number of quotations, and interesting anecdotes, to relieve the fatigue of his reader. He would have done this, had it been in his power.

But the nature of his situation, and his constant engagement in an employ, which nearly engrosses his time, precluded his collecting, either from reading or conversation, such quotations or anecdotes, as would suit his purpose.

ADVERTISEMENT.

TO THE THIRD EDITION. In this edition the work has been corrected, and so much increased as to be one-third larger than before : particularly the articles of Pre sumption and Analogy have been much more fully discussed. The author has taken pains to make the Table of Contents as full as he was able, so as to amount to nearly a complete ana lysis of the book. His object in doing so, is, first, to enable the student with greater ease, not only to refer to such parts as he wishes, but also to ascertain from time to time, in the course of his reading, whether he understands and re members what he has read ; and further, to re fresh his memory with its contents at any future time : — and, in the next place, to render it more easy for a tutor to examine his pupils, at the beginning of every lecture, as to whether they comprehend and remember what they read in the preceding lecture.

This practice will be found to contribute to their improvement more than any other. TABLE OF CONTENTS. Page Preface to (he first edition iii Advertisement to the third edition xii

Chapter I. On The Nature Of Moral Evidence

; AND WHEREIN IT DIFFERS FROM DEMONSTRATION. Moral evidence explained 1 Distinguished from the evidence of morality 2 Differs from demonstration 1 . As to its subjects 3 2. As to the method in which it is conducted 3. Because the arguments on both sides of a question must be considered 4 4. Because propositions in moral evidence, though false, are not absurd 5. As to the kind of assent it produces 5 6. Because it affords no rule for judging with certainty — 7. Because it admits of degrees 6 8. Because it admits of an accumulation of proofs. • • • 9. Because you cannot reason safely farther than one step 7 10. Because it does not compel the asscut CONTENTS. Page 11. Because it does not admit as great precision in language 12 Is inferior to demonstration, yet not to be rejected, and whv Is suited to our state as moral agents 13 Two extremes from not attending to the difference between moral evidence and demonstration. (1) Calling probable proof demonstration 15 (2) Disputing probable proof, because not demonstrative 16 What ought to be regarded as proof 17

Chapter II. On The Different Kinds Of Moral Evidence, With Observations On

THE WEIGHT OF EACH. 1. Personal observation or experience 17 ( 1 ) Of things uniform 18 The method of reasoning respecting them- « • • • • 19 (2) Of things various. Mode of reasoning respecting them 27 The folly of pretending to judge by experience, and yet decrying general rules 29 2. Testimony 32 1 . Divine testimony 33 2. Human testimony. Defined Is the evidence of one witness, or morels direct, or incidental* » • 34 Is simple, or confirmed by oath 35 Is spoken, or written 36 On the credit given to testimony 37 Remote testimony • 42 3. Observation of others . Relates to subjects which are uniform, or various . . CONTENTS. XV Page Is the source of the greater part of our knowledge 43 The weight of its evidence depends 1. On the nature of the subject, whether or not easily understood 2. On the character of the observers 44 3.

On the number of our informers. 4. When all who speak of Lthe subject agree, and their account accords with our own observation, it is a maximum • 45 Yet inferior to demonstration 46 Its weight is confirmed when it agrees with personal observation, and lessened when it disagrees. • • • 48 When personal observation may be corrected by the observation of others 4. General notoriety. Explained 51 Most facts, and general truths are believed on this evidence On what its weight depends 52 5. Report. — Explained. — Its weight 53 0. Tradition. — Explained 54 All these kinds of evidence are external. Besides these there are internal : as 1. Inferences from facts 1. Presumptions 55 Defined, and illustrated by examples How its weight is to be estimated 57 A mistake respecting it pointed mit • •• • Experience is the ground of presumptive evidence, and also its measure 59 (1) In relation to things uniform 60 (2) In relation to tilings various 61 Whether presumptive evidence is always overturned by positive proof 66 Analogy is a peculiar species of presumption • • • • 68 Explained, — Its weight CONTENTS.

Page 2. Tables of the probabilities of the duration of life, and the doctrine of chances 6!> 3. Inferences from premises 4. The consistency of the parts of a relation 70 General remark respecting the different kinds of moral evidence. 71

Chapter III. General Directions Relating To Moral Reasoning

I. Previous qualifications 73 1. A sincere desire to know the truth- 2. Acquire fixed principles of evidence, and a habit of applying them steadily 77 3. Get a habit of inquiring after a standard 78 4. Acquire a habit of referring things to their end- •• • 79 5. Acquire precise rules of judgment- II. To determine whether we should engage in the discussion 81 1. Consider whether the question is worth investigating 2. Will it admit of free examination 3. Is it capable of a satisfactory decision 83 4. Are we competent to the discussion 84 5. When it is to be debated with another, we should consider whether he is likely to be convinced- • • • III. When we have determined to engage in the investigation, we should 1. Keep in mind that our decision should depend on the evidence sot the facts, &c. and not on the iffects of admitting or rejecting them 89 2.

Examine if the question is stated fairly 92 3. Form clear ideas of the proposition • 4. Consider of what kind of evidence it admits •••-.. CONTENTS. XVll Page 5. Our judgment of future events is to be determined by probability, not possibility 94 6. Consider all the arguments on both sides 97 7. Guard against the fascinations of expression ■ 8. Guard against the delusions arising from the im perfection, and the abuse of words 98 9. Trace contests up to their origin 101 10. Distinguish real reasons from pretences 103 11. Guard against the mis-statement of degrees. • • . 12. Proof depends on the weight of arguments, not their number 104 13. Determine the weight of each argument, sum up, and balance 14. If both sides be equal, suspend the judgment, not otherwise 105 15. Guard against the impression made by injudicious attempts to support a cause IV.

To determine the weight of any argument, or the probability of any event 107 Draw your conclusions from experience, not from arguments a priori 109 To determine the degrees of probability 114 Cautions, 1. Make your observations on as large a scale as possible 117 2. Take care that the circumstances are similar.. . . 118 Often, the exact degree of probability cannot be ascertained 124 How to proceed in cases of extraordinary importance 128 Compound probability 135 How to judge by the general appearance of a question, and by the manner in which it is treated. . 137 How to regulate our choice 140 1. State all advantages and all disadvantages 141 u CONTENTS. Page 2. Consider remote consequences 141 3. Examine whether the advantages and disadvantages are stated fairly 142 4. On contingent advantages 1 13 To determine on the pursuit of a proposed object. . 144 How to regulate our advice to others 148

Chapter IV. Special Directions Relating To Each Kind Of Moral Evidence

I. Personal observation, and the observation of others 149 1. Consider whether you, or they are competent observers 2. Ascertain the circumstances under which the observations were made 152 3. Do not draw conclusions from too few subjects : or proportion your assent to the extent of your materials 153 4. In subjects which are various, how to ascertain what is probable, and the degree 154 5. Subjects which are various do not admit of conclusions which are constant 155 (5. Take care how you form systems 1 56 7. The truth of an hypothesis cannot be inferred from its solving all the phenomena belonging to the subject Further cautions on the observations of others 157 1. Do their facts and processes warrant their conclusion 2. Do their observations coincide with your own. . 3. Credit is due to every man in his own profession. — On the constant resistance of proposed improvements , .

CONTENTS. XIX Page 4. No opinion is entitled to weight on account of its antiquity ■ 161 II. Testimony 162 1. Is the thing credible 163 2. Are the parts of the relation consistent with each other, and with known circumstances 108 3. Does the relation agree with subsequent circumstances 1(39 4. Is the witness competent to judge of the fact- •• • — 5. Can he recollect it 170 6. Is he interested in the decision 7. On a testimony against the interest of the witness 172 8. Did he speak his real judgment 173 9. Is he a man of integrity 175 10. Is he a man of general veracity 178 How far a general liar is entitled to credit .... 179 11. On the manner in which the evidence is given- • 185 12. On the occasion on which it is given 13. On the testimony of a dying man--- 14. Does the evidence rest on the testimony of only one witness, or more 189 15.

Could the account be easily confuted, if false- • 190 16. A vague account not as credible as a particular one li>l 17. When the witness speaks positively of some things, aud with hesitation of others 18. Of ancient facts ; what reception did they meet with at first 192 19. On the omission of a thing pretended to have been public W 20. On contradictory testimony What testimony is negative and what positive. • 199 21. Whether a negative can be proved 2U1 22. On testimonies agreeing in part, and contradictory in part 203 ■> XX CONTENTS. Page Remote testimony 205 III. General notoriety IV. Report • • 207 V. Tradition 208 VI. Inferences from facts, or premises — Presumptive evidence. — Caution respecting- ■ • • — Rule relating to 213 Analogy. — Weight of evidence depends 214 (1) On the number of points of resemblance- • 215 (2) On the degree of likeness in each (3) On experience (4) The more extensive our experience, the safer our reasoning 216 (5) The most important consideration is, whether the two subjects resemble each other as to the principle on which the conclusion depends 218 Competition of opposite analogies 223 On inferences from premises, and the doctrine of chances 227

Chapter V. On The Kinds Of Evidence Of Which Different Subjects Admit

AND ON WHICH THEY ARE ACTUALLY BELIEVED : TOGETHER WITH DIRECTIONS, AS TO THE EVIDENCE ON WHICH THEY OUGHT TO BE RECEIVED OR REJECTED 227 1. Mathematical truths 228 2. Moral maxims and proverbs- 3. Subjects of natural history • 229 4. Effects of certain substances on mankind 231 5. The constitution and changes of the heavenly bodies CONTENTS. XXI Page 6. Present facts, as the existence of cities, buildings, &c. 233 7. Of hand-writing- 8. Effects of institutions tjn the characters, manners, &c. of the people 234 9. The knowledge of mankind 235 10. The knowledge of men's motives, intentions, &c 236 1. When stated ; they may be stated (1) fairly : yet misunderstood.— Why. — To understand them 1. we should consider what their expressions usually mean, under similar circumstances 239 2. Should interpret them so as to make their statement consistent with itself, and with the principles by which men are usually actuated 3.

Conditional threats should be distinguished from absolute 241 4. Conditional promises should be distinguished from absolute 242 (2) Deceitfully. — They may assign pretences for reasons How to distinguish them « 243 May have changed their intentions, or principles ■ 245 How this may be discovered • The chief difficulty as to this 248 2. When intentions are not stated, must be inferred from actions 250 Can they be bo inferred ? • When a single act will not warrant the inference, repeated acts may fully warrant it---- 253 Where the same conduct may arise from different motives, the true motive must be determined from circumstances CONTENTS. Page How far the avoiding of a trial is an evidence of guilt 255 Whether the having published what is reproachful to another, is a proof of a criminal intention 261 Under what circumstances silence indicates consent 268 11.

On our transactions with mankind 269 12. On our judgments of the future conduct of men, or of their unknown past or present conduct- • 273 13. Of transient facts or events 278 14. Of recent events examined in courts of judicature 280 15. Of recent public events, as battles, &c. 281 16. Of the evidence of history 283 When a contemporary historian has the advantage 288 Accounts published while events are taking place are sometimes worthy of greater credit, than those given afterwards 289 Historical facts relating to contests between nations must be traced to their origin, and through every step of their progress 291 On judging of contests between rulers and subjects 294 To determine the temper of the times at any period 296 To decide on the characters of public men • - - • 297 To decide on hostile characters 298 To decide en eminent characters in history .... 299 17.

On the evidence of memoirs 300 18. On the history of remote periods 301 19. Of Parliamentary debates 20. On the authenticity of books 304 21. Of miracles 303 Review of the chapter gjj CONTENTS. XXIII Page CONCLUSION. 1. Experience is the grand test of probability: but affords no help in determining the morality of actions 312 2. Experience furnishes only the materials of knowledge 314 3. Ability in moral reasoning, is a later acquirement than in demonstration 4. Errors on practical questions are not innocent, unless inevitable 315 5. Morality is of little practical use without moral evidence 316 6. An honest mind conduces more to a correct judgment of things, than great talents or acquirements Appendix AN

INTRODUCTION.

TO THE STUDY OF MORAL EVIDENCE.

Chapter I. On The Nature Of Moral Evidence

: AND WHEREIN IT DIFFERS FROM DEMONSTRA- TION. Moral evidence is that species of proof, which is employed on subjects, directly or indirectly, connected with moral conduct. It is not, however, confined to such subjects;, but is extended to all those facts, and events, concerning which we do not obtain the evidence of sense, intuition, or demonstration, and to all the general truths which are deduced from observation. In these, it still retains the name of moral evidence, a denomination which it seems to have derived from its having been originally employed on sub jects connected with moral conduct : because a Nature of Moral Evidence, [ch. Ithey form the most important class of subjects to which it is applicable. The evidence of morality must be carefully distinguished from moral evidence : — a caution which it is the more necessary to give, because they have been confounded, and that even by persons from whom a clear and distinct view of such sub jects might have been expected.

The former is that evidence, by which any class of actions is proved to be virtuous or vicious : the latter is that, by which facts or events are proved to be true or false. These two species of evidence are, however, very frequently connected. For, moral conduct requires, in most cases, an appli cation of moral evidence ; as the laws of morality can rarely be applied for the direction of our actions, without a knowledge of facts. Thus, in order to apply the moral rule, that a man should pay his just debts, it is necessary to know what is a just debt; and, to ascertain this will require a knowledge of facts. That, in politics, a man should support those measures only which are substantially just, is a moral duty; but, to de termine what measures are just, requires a know ledge of facts, as well as of the principles of jus tice.

Moral evidence and demonstration differ in several particulars, which it may be useful to mention. 1. They differ as to their subjects. Demon stration is employed about abstract truths, and the necessary relations of ideas. Of this kind are the properties of numbers and of geometrical figures ; and, indeed, all subjects which are capable of being accurately expressed by numbers, as extension, duration, weight, velocity, and force. But, the subjects of moral evidence are matters of fact, and the connections, whether constant or variable, which subsist among things which actually exist. Thus, that Romulus founded Rome, that water freezes at the tem perature of thirty-two degrees, that fire softens wax but hardens clay, are truths within the province of moral evidence. 2. They differ as to the method in which they are conducted.

In demonstration, we proceed from known truths to those which are unknown, by steps, each of which is necessarily connected with that which precedes it. In a moral proof, there is no such necessary connection between its parts. It generally consists of arguments, which are wholly unconnected with each other ; and where there exists a connection between the arguments, that connection is not a necessary, but only a probable one. Or, to express this differently, a demonstrative proof consists of one series, each part of which is dependent on that which precedes it ; but a moral proof generally b2 Nature of Moral Evidence, [ c h . i • consists of a number of independent arguments. Thus, the proof of every proposition in Euclid's Elements consists of a series of arguments con nected together so as to form one chain, in which, if any one link fails, the proof fails.

But the proof, that the Romans were formerly in this island, consists of various independent arguments ; as, the testimony of each historian who mentions the fact, the Roman camps and roads, the remains of Roman buildings, the coins, and urns, the tessellated pavements, &c. These are so many arguments, each independent of the rest, but all conspiring to prove the fact. 3. In demonstration, it is not necessary to consider more than one side of a question ; for, if, by a demonstration justly conducted, any proposition is proved to be true, it is of no con sequence what may be urged against it; for, whatever is offered as proof on the opposite side, must be a mere fallacy. But, in moral evidence, there are very frequently, perhaps generally, arguments of some weight on both sides; and therefore, before we can decide, we must examine both sides of the question, and give our assent to that on which there appears to be the greatest weight of evidence. 4.

Propositions, contradictory to those which are established by moral evidence, are merely false : but those which are contradictory to such as may be demonstrated, are not only false, but absurd also. Thus, the assertion that there is no such city as Pekin, though false, is yet not ab surd; for there was a time when it was true. But the proposition that ' the three angles of a triangle are not equal to two right angles,' is not only false, but also involves in it an absurdity. 5. There is a difference also in their force, or in the kind of assent which they produce. As, in demonstration, there is a necessary connection between each successive step of the proof, the ideas compared are perceived to agree or disagree. But, in moral evidence, their agreement or disagreement is only presumed; and that on proofs, which are, in their nature, fallible.