Context

This Section concludes Part III of Book I by supporting its main thesis: that belief is a lively idea formed from a present impression due to experience of constant conjunction.

Background

In the Discourse on Method, Part V, Descartes had argued that non-human animals are destitute of reason, as are all mechanical devices. He devised two tests to show that this is the case. The first is that animals are not capable of rational discourse by which to express their thoughts. The second is that they do not have general problem-solving capacities, despite their being able to perform specialized tasks on the basis of the disposition of their organs. Malebranche, in Book VI, Chapter VII of The Search after Truth, supported the Cartesian position against those who, in the name of Aristotle, pretend to prove that Beasts feel, will, think, and argue, even as we do, though in a more imperfect manner. He claims that the question comes down to whether matter alone can perform these functions, and he finds it to be evident that no configuration or motion of matter can do so. Empirical evidence of the intelligence of animals, such as that cited by the author in the present Section, is taken by Malebranche only to be evidence of the intelligence of their designer, God.

The Treatise

1. The author takes it to be an evident truth that beasts are endow’d with thought and reason as well as men. So strong are the arguments for this position, that they would never escape the most stupid and ignorant. The defense of the thesis will accordingly be short, as it is nearly as ridiculous to spend much effort in defending an evident truth as to deny it.

2. We observe that we humans adapt our means to our ends, guided by reason and design. We wish to preserve ourselves as well as to obtain pleasure and avoid pain, and to attain these ends we do not act ignorantly nor casually. In millions of cases, we see non-human animals acting in exactly the same way, directing their means to their ends, so that all our principles of reason and probability carry us with an invincible force to believe the existence of a like cause [of their actions, namely, reason and design]. It is needless to give examples, as the resemblance between ourselves and the animals is so great that the observation of a single case is enough to provide an incontestable argument for the present doctrine.

3. Besides being obvious, the doctrine of the similarity between humans and animals is useful in the conduct of the philosophy of human nature, by supplying a kind of test of its plausibility. We judge the similarity of the internal actions of the two on the basis of the similarity of their external actions. This line of reasoning may be extended to the causes of the internal actions: they should be thought to be the similar in both cases as well. Any true hypothesis regarding the causes of internal actions should therefore explain them in both man and beast, and failure to do so is an indication of their falsehood. The common way in which philosophers explain those actions, is by way of very subtle and refined thought, of which not only animals, but also children and ordinary adults are not capable. Yet those persons are capable of the same emotions and affections as persons of the most accomplish’d genius and understanding. The appeal to a subtlety that cannot explain the existence of these phenomena proves the falsehood of systems invoking it, and conversely, a system that explains it by appeal to a simple mechanism is proved to be true.

4. The author proposes testing his system to see whether it can account just as well for the reasonings of beasts as it can for the reasonings of humans.

5. He begins by distinguishing between two kinds of actions. The common actions are such as those of a dog that avoids fires and cliffs, shuns strangers, and caresses its master. The more uncommon actions are those which involve a kind of wisdom or foresight, such as when a bird builds its nest and raises its brood with a precision befitting a chemist.

6. The author is concerned to explain the first kind of action. [The second kind is analogous to the subtle reasoning that he rejects as the cause of most human action.] The reasonings of humans and animals are based on the same principles in these cases. There are two components of such reasonings. The first is that the judgment resulting from the reasoning be preceded by an impression of sense or memory. In the case of a dog, the impression of a certain tone in the master’s voice indicates his anger, and the dog anticipates punishment. An impression of smell informs the dog that there is a game animal nearby.

7. The second component is the role of experience and observation of the conjunction of similar impressions with specific kinds of objects in the past. Varying the experience varies the animal’s reasoning. If the master gives some sign that he will beat the dog at one time and then changes the signal to another one later, the dog will draw the conclusion from different impressions, guided by his most recent experience.

8. [The author’s system has accounted for the origin of belief in customary conjunction discovered in experience.] He states that if another system can account for belief without appeal to these elements and can explain the reasonings of animals thereby, he promises to endorse that explanation. On the other hand, he expects an equitable condition from his opponent: if the only account of belief that can explain these reasonings is his own, then the author’s system should be receiv’d as entirely satisfactory and convincing. He quickly adds that it is it is evident almost without any reasoning that his system alone can supply the explanation. First, animals certainly are unable to perceive real connections among objects. The only way they can make inferences about such connections is from experience. Second, the inferences are not drawn from the general premise that those objects, of which they have had no experience, resemble those of which they have. The only way that they could draw the inference is by becoming accustomed to their union on the basis of experience. The author has made this sufficiently evident in the case of humans. But with respect to beasts there cannot be the least suspicion of mistake; which must be own’d to be a strong confirmation, or rather an invincible proof of my system.

9. We take for granted the operations of our own reason while marveling at the instincts in animals, which we have difficulty in explaining them in terms of the principles that explain the workings of our minds. But this only serves as the most powerful proof of the force of habit in reconciling ourselves to what appears to us. The right way to view the matter is to reconcile ourselves to the view that reason itself is nothing but a wonderful and unintelligible instinct of our souls, which carries us along a certain train of ideas, and endows them with particular qualities, according to their particular situations and relations. Although the instinct is based on observation and experience, we do not understand why those causes bring about their effect upon our ideas [i.e., enlivening them to the point of becoming beliefs], any more than we understand why nature might not bring about this effect independently of observation and experience. Nature assuredly could bring about belief unaided by observation and experience. But even if it does bring it about through habit, habit is nothing but one of the principles of nature, and derives all its force from that origin.

The Enquiry

Section 9 of the Enquiry has the same title as the present Section, and its content is substantially similar. Hume begins by recounting his explanation of our experimental reasonings, which he here describes as being based on an analogy between the present situation and past observation of causes. Where there is exact similarity, the conviction drawn from it is regarded as certain and conclusive, and the strength of the conviction in cases of dissimilarities is proportional to the number and kind of differences. This feature of our reasoning is applied to Hume’s account itself. He expresses the hope that if the same mechanisms that operate in the human understanding and in the production of human passions must be invoked to explain the behavior of non-human animals, this will serve to confirm all of our former observations. Hume describes two key aspects of animal behavior: that they learn from experience, and that they learn through custom. Regarding the first point, he notes that animals do make inferences that take them beyond what is present to their senses. He claims further that these inferences are based on the presupposition that their future experience will resemble their past experience. This can be seen from the fact that experienced animals make wiser choices than do fledglings, and that animals can be trained with rewards and punishments. As to the second point, he cites the imperfection of an animal’s understanding, which is not equipped to engage in 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. In this, animals are like children, or even philosophers in their practical lives. The kind of inference under discussion is too important for nature to have left to the hesitations and uncertainties of reasoning. It is clear that nature has endowed animals with a non-rational capacity for these inferences, and by analogy, we ought to infer that human animals are endowed with it as well. There are other capacities of animals that do not depend on experiences, and these are what are properly called instincts, which we humans admire as something very extraordinary, and inexplicable by all the disquisitions of human understanding. Yet they should not be seen as exceptional when we consider that 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 and 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. The instinct by which humans avoid fire is as much an instinct as that by which a bird builds its nest and cares for its young. In a footnote, Hume lists the principal differences between the inferential capacities of humans, which he claims will allow the reader to comprehend easily the differences between humans and non-human animals.