PART I: CIRCUMSTANTIAL EVIDENCE (1913.)1 3. JOHN H. WIGMORE. Principles of Judicial Proof. Classification of Circumstantial Evidence. Two important considerations affect the classification of circumstantial evidence for convenient treatment. (1) The starting point of the classification should be the proposition desired to be proved (Probandum), rather than the evidentiary fact offered. The fundamental inquiry whether the claimed conclusion is a probable inference from the offered fact. Now if we take a specific probandum as the starting point, and ask in turn, whether it is relevantly evidenced by fact a, fact b, fact c, and so on, we are able to compare intelligently, without repetition, the various sources from which the conclusion or proposition is capable of being inferred. (2) A second consideration is that we are here dealing, not with a general scheme of human life or of modes of proof, but with a limited body of rules brought forth by problems laid before the Courts for adjudication. Not every species of evidentiary fact or of inference is brought into the realm of judicial evidence, but chiefly certain common and frequently recurring matters affecting the usual crimes and civil disputes. With these considerations in mind, the general grouping of Probanda may be made as follows: I. An Event, Quality, or Condition of Physical (Inanimate) Nature; II. The Identity of a Thing or Person; III. A Quality or Condition of a Human Being; IV. The Doing of a Human Act. Further, under each group, it will be often convenient to arrange the evidentiary facts according as the proof or indication they afford is: A. Prospectant; B. Concomitant; or C. Retrospectant.2 The distinction between the first and the third heads is always marked and often useful in hints. For instance, under Group IV, above, the evidentiary facts of Character, Plan or Design, Motive, point forward to a future act; i.e. we take our stand before the time of the act, and argue that because of the person's character, design, or motive, he was likely, or not, to do the act in the future; while the fact of Consciousness of Guilt points backwards, i.e. we infer from his state of mind that he has been guilty of some crime in the past. In evidencing matters under Group III, this distinction 1 Adapted from the same author's Treatise on Evidence (1905, Vol. I, § 43). 2 It is perhaps worth noting that this analysis was long ago hinted at by Burke, in his disquisition on evidence in the Report on Warren Hastings' Trial, in 1794 (31 Parl. Hist. 342); "every circumstance," he remarks, "precedent, concomitant, and subsequent, become parts of circumstantial evidence." Mr. Burrill's treatise on Circumstantial Evidence also uses the same classification. becomes also useful; e.g. the fact of hereditary insanity as pointing forward to a defendant's insanity raises a question of relevancy essentially different from that raised by evidence of abnormal conduct exhibited by him; so also in proving an emotion or passion (motive), evidentiary circumstances such as family relationship, need of money, and the like, are offered as pointing forward to the probability of such an emotion being excited, while outward exhibitions of conduct, used for the same purpose, have a retrospectant value as showing that the emotion was the probable source of the evidentiary conduct. This distinction, then, while not always an essential one, at least provides a convenient order of arrangement, and is often serviceable in emphasizing related qualities of probative value. TITLE I: EVIDENCE TO PROVE AN EVENT, CON- 4. JOHN H. WIGMORE. Principles of Judicial Proof. (1913.)1 § 1. Classification of Probanda. There can be, at certain points, no sharp distinction between a Human Act, a Human Quality or Condition, and a Physical Fact (External Inanimate Nature), with reference to evidencing them as probanda. Some matters, such as death, may sometimes be viewed in either the first or the second aspect; for other matters, such as the possession of land, it may not be easy to distinguish between the second and the third. The propositions which come to be proved before tribunals of justice embrace every sort of fact in life, and no classification not purely arbitrary can divide them for practical purposes into classes always absolutely distinct. But in the present group the distinguishing feature is the absence of the element of a human will and of the human emotion, reason, and character as affecting conduct. The kinds of probanda may be further subdivided into four categories: I. Identity (for example, whether a machine delivered was the same as the one agreed to be delivered); II. Occurrence of an Event (for example, whether a tree fell, or whether lightning struck a house); III. Existence, or Persistence, in Time (for example, whether a defect in a street or a house was in existence at the time in issue); IV. Tendency, Capacity, Quality, Cause, or Effect (for example, whether a place in a sidewalk was dangerous, or whether a gunshot could carry a certain distance). Here, again, no specific single terms can accurately distinguish the different groups, nor is it possible always to draw the lines sharply between the various groups. A given evidentiary fact may and usually does involve (as already observable in dealing with the other materials) more than one of these processes of inference. For example, in proving a sidewalk hole to be unsafe, the evidence may be that A fell there two weeks ago; this involves, first, an inference in the fourth group, namely, that the place was then unsafe, 1 Adapted from the same author's Treatise on Evidence (1905, Vol. I, §§ 432 461). and, secondly, an inference in the third group, namely, that its unsafeness two weeks before evidences its unsafeness at the time in issue; and either of these inferences may be rejected as unsound, while the other remains sound. Again, to prove the identity of a bale of goods delivered, its features six months before may be offered; and this involves the soundness of two inferences, one of the first and one of the third sort. Again, the question being whether a tree was lying across a street on January 1, the evidentiary fact that the tree was struck by lightning on July 1 preceding involves two inferences, namely, that the tree fell when struck, and that its fallen condition continued till the time in question, i.e. an inference of the second and one of the third sorts. Again, to show that a dust explosion occurred in a certain room, the evidentiary fact that a dust explosion previously occurred in the same room involves two and perhaps three inferences, - first, that there is a tendency in a room thus circumstanced for the dust to explode spontaneously, secondly, that as a result of this tendency an explosion did occur, and perhaps (intervening between these two), thirdly, that the condition at the previous time continued up to the time in question, inferences, respectively, of the fourth, the second, and the third sorts. In spite, however, of this incidental resort to two or more of the kinds of inference in one piece of evidence, the kinds of inference, as types, remain distinct. § 2 (I). Identity of One Object with Another. The mode of inference used in proving identity is precisely the same for objects of inanimate nature and for human beings and will be examined post, No. 14. § 3 (II). Occurrence of an Event. This term includes theoretically matters which might perhaps be conceived of also under the category of Existence. For example, if the probandum be the destruction of a house, it might ordinarily be conceived of either as an event, the momentary fact of destruction, or as a condition of existence, the state of being destroyed.1 For practical evidential purposes, however, the choice of terms is here not important. The distinction between the second and the third groups is the distinction between the mere fact of occurrence or existence as such, and the fact of occurrence or existence with reference to time. In the present group it is asked how to prove the mere fact of destruction or non-destruction. § 4. Same: Occurrence of an Event, as evidenced from Cause or Effect. An event may be evidenced circumstantially by a cause or by an effect. This mode of inference is available in the three forms already mentioned (ante, No. 2), - Prospectant, Retrospectant, and Concomitant. For example, the sinking of a ship is evidenced prospectantly by the presence of a storm in the vicinity; the occurrence of a fire is evidenced retrospectantly by the blackened ruins left as its traces; the revolution of car wheels is 1 "When successive phenomena are in question, these abstracted portions [factum probandum and evidentiary fact] may always themselves be viewed as events, even where so uneventful as hardly to deserve the name in popular language. Thus, where any quality of anything changes ever so slightly say, when a thermometer rises one degree - we have what is here considered an 'event.' . . It may seem [in these examples] strange to call a large river or a large town 'events,' but here the names are only used elliptically, for the growth of the town and the continued existence of the river." (Sidgwick, Fallacies, pp. 333, 338.) evidenced concomitantly, by the motion of the car, to the person riding in it. This type of inference, though perhaps in practice the commonest of all, gives rise, nevertheless, to practically no judicial problems. One reason for their rarity is that, for the occurrences of external or inanimate nature, testimonial evidence is commonly abundant. Another reason is that, where the desired inference transcends the scope of ordinary instinct and experience, it is offered as the subject of a testimonial knowledge or opinion by an expert witness, as where a physician testifies that froth in the lungs of a corpse evidences a certain kind of death. Another reason is that most events of external nature are associated with some human act, and hence the proof involves evidence of the act. But a reason the most important for present purposes is that an inference of this type, though in form the first one to be put forward as the main inference, frequently if not usually — resolves itself into another of a different type, and the evidential question comes to turn upon the other. This feature it is necessary to explain more fully. The process may be examined for each of the three modes of inference in turn, prospectant (inference from a prior or causal fact), retrospectant (inference from an effect), and concomitant. (1) Prior Cause, as the Basis of Inference. That a corporal injury will cause a permanent disability to work; that noxious fumes will cause the destruction of herbage, these are examples of this sort of inference. The evidential offer may be put in this way: The fact of noxious fumes is offered as evidence that at a future time there will ensue no herbage. But, in practice, these offers involving an argument from cause to effect do not raise any evidential questions in the above form, but resolve themselves into others; because the inference rests on an important assumption, which in its turn becomes the subject of a new evidential question. To take the second illustration above, and state it more accurately: The fact of these fumes haring a tendency to destroy herbage evidences that in future they will probably result in destroying the herbage in question. Now this form of statement brings out the necessity of proving, in its turn, a fact of a new and different category, viz. this assumed tendency of the fumes to destroy herbage; and this fact of tendency (or capacity) is seen to be in reality the probable point of controversy. (2) Subsequent Effect, as the Basis of Inference. That the falling barometer indicates the existence of an atmospheric disturbance; that the derailed car indicates the prior occurrence of a collision or other destructive event, - these are instances of inferences from effect back to the existence of a cause. Such inferences, however, rarely raise evidential questions in practice, for reasons the same as those just explained. Thus, in the illustration above used, the destruction of the herbage is evidently relevant, without question, as indicating the same destructive influence of atmosphere, soil, or the like; but in the further process of fixing on the fumes in question as the precise cause, either we proceed to offer that specific inference through an expert witness, who asserts as a matter of professional experience that the appearance of the herbage indicates specific fumes as the source (in which case no questions of circumstantial relevancy arises), or, in attempting otherwise to fix upon the fumes as one of the probable destructive influences, it must first be shown that they have this tendency to destroy herbage. Thus, in general, the inference from an effect to the existence or operation of a cause usually leads to a new controversy as to whether the supposed cause has any causing tendency of the alleged sort, and this new controversy involves a different sort of inference. (3) Concomitant Events, as the basis of Inference. An event cannot be inferred from its concomitant event except on the assumption that they have a common cause, or unless the inference is really not one of concomitancy, but of cause and effect. An example of the latter sort is the inference of fire from smoke, i.e. it is really the inference of fire as a cause from smoke as the effect. An example of the former sort is the inference of revolving wheels from the motion of the car, i.e. there is really an inference, first from the motion to the motive power as a cause, and next, from the motive power to the revolution of the wheels as a common effect of the same cause. no separate problem is involved in this form of argument. Hence, § 5 (III). Existence (or Persistence) in Time. There is, in strictness, no place for a separate category of mere Existence, as distinguished from Occurrence; for, as above suggested, the notion of a thing's either coming into being or of its having been in being is an inclusive and single notion, with reference to which inferences from cause or from effect may equally be made. Thus in inferring future disability from corporal injury, it is immaterial whether the former be termed the occurrence of an event or the existence of a condition; the inquiry is merely how far we may infer towards it from something else as its cause or its effect; and the term Occurrence has therefore been employed as the one most generally applicable to the probandum. Nevertheless, it is convenient to separate, for some purposes, a category of Existence in Time as the probandum, i.e. those instances in which the Existence in Time of an object, condition, or quality is to be evidenced by a prior, subsequent, or concomitant existence. The inference may, as usual, be of one of these three general types; but the first two are not dissimilar in their operation, and may be considered together. § 6. Same: (1) Existence, from Prior or Subsequent Existence; General Principle, applied in Sundry Instances (Highways, Machines, Buildings, Railway Tracks, etc.). When the existence of an object, condition, quality, or tendency at a given time is in issue, the prior existence of it is in human experience some indication of its probable persistence or continuance at a later period. The degree of probability of this continuance depends on the chances of intervening circumstances having occurred to bring the existence to an end. The possibility of such circumstances will depend almost entirely on the nature of the specific thing whose existence is in issue and the particular circumstances affecting it in the case in hand. That a soap bubble was in existence half an hour ago affords no inference at all that it is in existence now; that Mt. Everest was in existence ten years ago is strong evidence that it exists yet; whether the fact of a tree's existence a year ago will indicate its continued existence to-day will vary according to the nature of the tree and the conditions of life in the region. So far, then, as the interval of time is concerned, no fixed rule can be laid down; the nature of the thing and the circumstances of the particular case must control. Similar considerations affect the use of subsequent existence as evidence of existence at the time in issue. Here the disturbing contingency is that some circumstance operating in the interval may have been the source of |