Animal Reasoning

82. All our reasonings concerning matter of fact are founded on a species of Analogy, which leads us to expect from any cause the same events, which we have observed to result from similar causes. Where the causes are entirely similar, the analogy is perfect, and the inference, drawn from it, is regarded as certain and conclusive: nor does any man ever entertain a doubt, where he sees a piece of iron, that it will have weight and cohesion of parts; as in all other instances, which have ever fallen under his observation. But where the objects have not so exact a similarity, the analogy is less perfect, and the inference is less conclusive; though still it has some force, in proportion to the degree of similarity and resemblance. The anatomical observations, formed upon one animal, are, by this species of reasoning, extended to all animals; and it is certain, that when the circulation of the blood, for instance, is clearly proved to have place in one creature, as a frog, or fish, it forms a strong presumption, that the same principle has place in all. These analogical observations may be carried farther, even to this science, of which we are now treating; and any theory, by which we explain the operations of the understanding, or the origin and connexion of the passions in man, will acquire additional authority, if we find, that the same theory is requisite to explain the same phenomena in all other animals. We shall make trial of this, with regard to the hypothesis, by which we have, in the foregoing discourse, endeavoured to account for all experimental reasonings; and it is hoped, that this new point of view will serve to confirm all our former observations.

82. All our reasoning about matters of fact rests on a kind of analogy. It leads us to expect a cause to produce the same effects we have observed from similar causes. When the causes are entirely alike, the analogy is perfect. We regard the inference drawn from it as certain and conclusive. No one who sees a piece of iron doubts that it has weight and that its parts hold together. This has been true of every other piece of iron anyone has observed. But when the objects are not so exactly alike, the analogy is less perfect, and the inference is less conclusive. Even so, the inference still has some force, in proportion to the degree of similarity. Through this kind of reasoning, anatomical observations made on one animal are extended to all animals. For example, blood circulation may be clearly shown to occur in one creature, such as a frog or a fish. This certainly gives us strong reason to presume that the same principle applies to all animals. Such observations based on analogy can be taken further, even to the science we are now discussing. A theory may explain how the understanding works or how human passions arise and connect with one another. That theory will gain further authority if we find it necessary to explain the same phenomena in all other animals. We shall test this idea using the hypothesis we have offered earlier to explain all reasoning based on experience. We hope that this new perspective will help confirm all our earlier observations.

83. First, It seems evident, that animals as well as men learn many things from experience, and infer, that the same events will always follow from the same causes. By this principle they become acquainted with the more obvious properties of external objects, and gradually, from their birth, treasure up a knowledge of the nature of fire, water, earth, stones, heights, depths, &c., and of the effects which result from their operation. The ignorance and inexperience of the young are here plainly distinguishable from the cunning and sagacity of the old, who have learned, by long observation, to avoid what hurt them, and to pursue what gave ease or pleasure. A horse, that has been accustomed to the field, becomes acquainted with the proper height which he can leap, and will never attempt what exceeds his force and ability. An old greyhound will trust the more fatiguing part of the chace to the younger, and will place himself so as to meet the hare in her doubles; nor are the conjectures, which he forms on this occasion, founded in any thing but his observation and experience.

83. First, it seems clear that animals, like humans, learn many things from experience. They infer that the same causes will always produce the same events. In this way, they learn the more obvious properties of objects around them. From birth, they gradually build up knowledge of fire, water, earth, stones, heights, depths, and so on. They also learn about the effects these things produce. The ignorance and inexperience of the young clearly differ from the cunning and wisdom of the old. Through long observation, older animals have learned to avoid what hurt them and seek what brought comfort or pleasure. A horse accustomed to open fields learns how high it can jump. It will never attempt a jump beyond its strength and ability. An old greyhound will leave the more tiring part of the chase to younger dogs. Instead, it will position itself to meet the hare as it doubles back. The greyhound’s guesses about where the hare will turn are based on nothing but observation and experience.

This is still more evident from the effects of discipline and education on animals, who, by the proper application of rewards and punishments, may be taught any course of action, and most contrary to their natural instincts and propensities. Is it not experience, which renders a dog apprehensive of pain, when you menace him, or lift up the whip to beat him? Is it not even experience, which makes him answer to his name, and infer, from such an arbitrary sound, that you mean him rather than any of his fellows, and intend to call him, when you pronounce it in a certain manner, and with a certain tone and accent?

This is even clearer from the effects of training and education on animals. With the right use of rewards and punishments, animals can be taught any course of action, even one most contrary to their natural instincts and tendencies. Is it not experience that makes a dog expect pain when you threaten him or raise a whip to beat him? Is it not also experience that makes him respond to his name? From that arbitrary sound, he infers that you mean him rather than another dog. When you say it in a certain way, with a certain tone and accent, he infers that you intend to call him.

In all these cases, we may observe, that the animal infers some fact beyond what immediately strikes his senses; and that this inference is altogether founded on past experience, while the creature expects from the present object the same consequences, which it has always found in its observation to result from similar objects.

In all these cases, we may observe that the animal infers some fact beyond what it immediately senses. This inference is based entirely on past experience. The animal expects the present object to have the same effects it has always observed from similar objects.

84. Secondly, It is impossible, that this inference of the animal can be founded on any process of argument or reasoning, by which he concludes, that like events must follow like objects, and that the course of nature will always be regular in its operations. For if there be in reality any arguments of this nature, they surely lie too abstruse for the observation of such imperfect understandings; since it may well employ the utmost care and attention of a philosophic genius to discover and observe them. Animals, therefore, are not guided in these inferences by reasoning: Neither are children: Neither are the generality of mankind, in their ordinary actions and conclusions: Neither are philosophers themselves, who, in all the active parts of life, are, in the main, the same with the vulgar, and are governed by the same maxims. Nature must have provided some other principle, of more ready, and more general use and application; nor can an operation of such immense consequence in life, as that of inferring effects from causes, be trusted to the uncertain process of reasoning and argumentation. Were this doubtful with regard to men, it seems to admit of no question with regard to the brute creation; and the conclusion being once firmly established in the one, we have a strong presumption, from all the rules of analogy, that it ought to be universally admitted, without any exception or reserve. It is custom alone, which engages animals, from every object, that strikes their senses, to infer its usual attendant, and carries their imagination, from the appearance of the one, to conceive the other, in that particular manner, which we denominate belief. No other explication can be given of this operation, in all the higher, as well as lower classes of sensitive beings, which fall under our notice and observation ¹⁹.

84. Secondly, an animal cannot make this inference through argument or reasoning. It cannot reason that similar objects must be followed by similar events, and that nature will always operate regularly. For if arguments of this kind really exist, they are surely too obscure for such limited minds to grasp. Even a philosophical genius may need the utmost care and attention to discover and understand them. Animals, therefore, are not guided by reasoning when they make these inferences. Neither are children. Neither are most people in their ordinary actions and conclusions. Neither are philosophers themselves. In all the active parts of life, philosophers are much the same as ordinary people and follow the same principles. Nature must have provided some other principle, one that can be used and applied more readily and more generally. We cannot trust an operation as vital to life as inferring effects from causes to uncertain reasoning and argument. This might be doubtful in the case of human beings, but it seems beyond question in the case of animals. Once the conclusion is firmly established for animals, all the rules of analogy give us a strong reason to accept it universally, without exception or qualification. Custom alone leads animals to infer the usual companion of every object that strikes their senses. Custom carries their imagination from the appearance of one thing to the conception of the other, in the particular way we call belief. No other explanation can be given of this operation in any of the higher or lower classes of beings capable of sensation that we can observe ¹⁹.

85. But though animals learn many parts of their knowledge from observation, there are also many parts of it, which they derive from the original hand of nature; which much exceed the share of capacity they possess on ordinary occasions; and in which they improve, little or nothing, by the longest practice and experience. These we denominate Instincts, and are so apt to admire as something very extraordinary, and inexplicable by all the disquisitions of human understanding. But our wonder will, perhaps, cease or diminish, when we consider, that the experimental reasoning itself, which we possess in common with beasts, and on which the whole conduct of life depends, is nothing but a species of instinct or mechanical power, that acts in us unknown to ourselves; and in its chief operations, is not directed by any such relations or comparisons of ideas, as are the proper objects of our intellectual faculties. Though the instinct be different, yet still it is an instinct, which teaches a man to avoid the fire; as much as that, which teaches a bird, with such exactness, the art of incubation, and the whole economy and order of its nursery.

85. Although animals learn much from observation, nature also gives them much of their knowledge. This natural knowledge far exceeds the abilities they display on ordinary occasions. Even the longest practice and experience improve it little or not at all. We call these abilities instincts. We tend to admire them as extraordinary things that no amount of human reasoning can explain. But our wonder may cease or diminish when we consider another kind of instinct. We share with animals the ability to reason from experience, and our whole conduct in life depends on it. Yet this reasoning is itself only a kind of instinct or mechanical power that acts in us without our knowing it. In its chief operations, it is not guided by the relations or comparisons of ideas that our intellectual faculties properly deal with. The instinct that teaches a person to avoid fire is different from a bird’s instinct. But it is still an instinct, just as the bird’s instinct teaches it to incubate its eggs with such precision and to manage every part of its nest and its young.