dieren zijn rationeel
19 mei 1998
De tweede helft van de achttiende eeuw is een duidelijk keerpunt in de wijze waarop de mens zijn relatie tot de dieren begrijpt, ervaart en waardeert. De grens tussen mens en dier kwam nu te vervagen. Parker schetst deze ontwikkeling: "Essayists attempted to erase the human/animal boundary in two ways, claiming that humans are not so superior to animals morally, and that animals are almost the equals of humans intellectually. Some satirized the beastly morals of the scientific members of the Royal Society; others circulated stories about animal sagacity and credited animals with languages, albeit languages that, unlike Japanese or Spanish, had not yet been decoded by Englishmen. Meanwhile, scientists chipped away at definitions of human uniqueness that were based first on anatomy, then on intelligence, and finally on language."
Deze ideeën waren niet slechts voorbehouden aan een filosoferende elite maar vinden volgens Parker een oorzaak in de veranderende wijze waarop mensen in het dagelijks leven met dieren omgingen: "Less often were these people encountering wild beasts. With an improvement in their wealth, they were removing domestic animals from house to barn, and introducing non-productive animals (dogs, cats, birds) to the household as pets. Pet owners tended to doubt Cartesian orthodoxy about animals not feeling pain or being unable to understand their masters' words and commands. They credited animals with intelligence, discussed the existence and nature of their souls, and raised the possibility of them being included in the resurrection from the dead."
Er ontstond politiek verzet: "Puritans were the first to agitate against cock throwing and bear and bull baiting. Puritan objections were sustained during the Restoration period and extended to cockfighting. These sports were condemned not only for being painful to animals but also because it was thought that the pain that was originally brought about by human sinfulness should not be a source of pleasure to us. From the middle of the 18th century on, literature against the cruelty of bull fighting, cock fighting, and childrens' games in which animals were tormented swelled to a flood ... Voices were now raised against hunting that was conducted for no other end than sport. The Enlightenment movement for animal welfare was advanced by preachers and literary figures. Steele, Addison, Pope, and Johnson were powerful influences in the movement."
Aan deze lijst kan men ook de namen van Voltaire, Linnaeus, Rousseau en Bentham toevoegen. Zij waren allen geen vegetariërs. Wel hebben zij met succes een meer humane behandeling van dieren helpen bevorderen.
Ook David Hume (1711-1776) heeft een bijdrage geleverd door aan te voeren dat de grens tussen mens en dier niet langer als absoluut mag gelden. Onderstaand 'Of the Reason of Animals' uit A Treatise on Human Nature, Book I, Part I, Section XVI. Hume vecht hier met kracht van argumenten de stelling aan als zouden dieren niet rationeel kunnen handelen en denken. De tekst is in zijn geheel overgenomen uit Humane Thought:
Next to the ridicule of denying an evident truth, is that of taking much pains to defend it; and no truth appears to me more evident, than that beasts are endow'd with thought and reason as well as men. The arguments are in this case so obvious, that they never escape the most stupid and ignorant.
We are conscious, that we ourselves, in adapting means to ends, are guided by reason and design and that 'tis not ignorantly nor casually we perform these actions, which tend to self-preservation, to the obtaining pleasure and avoiding pain. When, therefore, we see other creatures, in millions of instances, perform like actions, and direct them to like ends, all our principles of reason and probability carry us with an invincible force to believe the existence of a like cause. 'Tis needless in my opinion, to illustrate this argument by the enumeration of particulars. The smallest attention will supply us with more than are requisite. The resemblance between the actions of animals and those of men is so entire in this respect, that the first action of the first animal shall please to pitch on will afford us an incontestable argument for the present doctrine.
This doctrine is as useful as it is obvious, and furnishes us with a kind of touchstone, by which we may try every system in this species of philosophy. 'Tis from the resemblance of the external actions of animals to those we ourselves perform that we judge their internal likewise to resemble ours; and the same principle of reasoning, carry'd one step further, will make us conclude that since our internal actions resemble each other, the causes, from which they are deriv'd, must also be resembling. When any hypothesis, therefore, is advanced to explain a mental operation, which is common to men and beasts, we must apply the same hypothesis to both; and as every true hypothesis will abide this trial so I may venture to affirm, that no false one will ever be able to endure it. The common defect of those systems, which philosophers have employ'd to account for the actions of the mind, is, that they suppose such a subtility (sic) and refinement of thought, as not only exceeds the capacity of mere animals but even of children and the common people in our own species; who are not withstanding susceptible of the same emotions and affections as persons of the most accomplish'd genius and understanding. Such a subtility (sic) is a clear proof of the falshood (sic), as the contrary simplicity of the truth, of any system.
Let us therefore put our present system concerning the nature of the understanding to this decisive trial, and see whether it will equally account for the the reasonings of beasts as for these of the human species.
Here we must make distinction betwixt (sic) those actions of animals, which are of a vulgar nature, and seem to be on a level with their common capacities, and those more extraordinary instances of sagacity, which they sometimes discover for their own preservation and the propagation of their species. A dog, that avoids fire and precipices, that shuns strangers, and caresses his master, affords us an instance of the first kind. A bird, that chooses with such care and nicety the place and materials of her nest, and sits upon her eggs for a due time, and in a suitable season, with all the precaution that a chymist (sic) is capable of in the most delicate projection, furnishes us with a lively instance of the second.
As to the former actions, I assert they proceed from a reasoning, that is not in itself different, nor founded on different principles, from that which appears in human nature. 'Tis necessary in the first place, that there be some impression immediately present to their memory or senses, in order to be the foundation of their judgment. From the tone of voice the dog infers his master's anger, and foresees his own punishment. From a certain sensation affecting his smell, he judges his game not to be far distant from him.
Secondly, The inference he draws from the present impression is built on experience, and on his observation of the conjunction of objects in past instances. As you vary this experience, he varies his reasoning. Make a beating follow upon one sign or motion for some time, and afterwards upon another; and he will successively draw different conclusions, according to his most recent experience ...
-Humane Thought (zj)