A LESSON IN THE ART OF DISTINGUISHING.
Father. Come hither, Charles; what is that you see grazing in the meadow before you?
Charles. It is a horse.
Fa. Whose horse is it?
Ch. I do not know; I never saw it before.
Fa. How do you know it is a horse, if you never saw it before?
Ch. Because it is like other horses.
Fa. Are all horses alike, then?
Ch. Yes.
Fa. If they are alike, how do you know one horse from another?
Ch. They are not quite alike.
Fa. But they are so much alike, that you can easily distinguish a horse from a cow?
Ch. Yes, indeed.
Fa. Or from a cabbage?
Ch. A horse from a cabbage? yes, surely I can.
Fa. Very well; then let us see if you can tell how a horse differs from a cabbage?
Ch. Very easily; a horse is alive?
Fa. True; and how is every thing called which is alive?
Ch. I believe all things that are alive are called animals.
Fa. Right; but can you tell me what a horse and a cabbage are alike in?
Ch. Nothing, I believe.
Fa. Yes, there is one thing in which the slenderest moss that grows upon the wall is like the greatest man or the highest angel.
Ch. Because God made them.
Fa. Yes: and how do you call everything that is made?
Ch. A creature.
Fa. A horse, then, is a creature, but also a living creature; that is to say, an animal.
Ch. And a cabbage is a dead creature: that is the difference.
Fa. Not so, neither; nothing is dead that has never been alive.
Ch. What must I call it, then, if it is neither dead nor alive?
Fa. An inanimate creature; there is the animate and inanimate creation. Plants, stones, metals, are of the latter class; horses belong to the former.
Ch. But the gardener told me some of my cabbages were dead, and some were alive.
Fa. Very true. Plants have a vegetative life, a principle of growth and decay; this is common to them with all organized bodies; but they have not sensation, at least we do not know they have—they have not life, therefore in the sense in which animals enjoy it.
Ch. A horse is called an animal, then?
Fa. Yes; but a salmon is an animal; and so is a sparrow; how will you distinguish a horse from these?
Ch. A salmon lives in the water, and swims; a sparrow flies and lives in the air.
Fa. I think a salmon could not walk on the ground, even if it could live out of the water.
Ch. No, indeed, it has no legs.
Fa. And a bird cannot gallop like a horse.
Ch. No; It hops upon its two slender legs.
Fa. How many legs has a horse?
Ch. Four.
Fa. And an ox?
Ch. Four likewise.
Fa. And a camel?
Ch. Four still.
Fa. Do you know any animals which live upon the earth that have not four legs?
Ch. I think not; they have all four legs, except worms and insects, and such things.
Fa. You remember, I suppose, what an animal is called that has four legs; you have it in your little books?
Ch. A quadruped.
Fa. A horse then, is a quadruped: by this we distinguish him from birds, fishes, and insects.
Ch. And from men.
Fa. True; but if you had been talking about birds, you would not have found it so easy to distinguish them.
Ch. How so? a man is not at all like a bird.
Fa. Yet an ancient philosopher could find no way to distinguish them, but by calling man a two-legged animal without feathers.
Ch. I think he was very silly; they are not at all alike, though they have both two legs.
Fa. Another ancient philosopher, called Diogenes, was of your opinion. He stripped a cock of his feathers, and turned him into the school where Plato, that was his name, was teaching, and said, “Here is Plato’s man for you!”
Ch. I wish I had been there, I should have laughed very much.
Fa. Probably. Before we laugh at others, however, let us see what we can do ourselves. We have not yet found anything which will distinguish a horse from an elephant, or from a Norway rat.
Ch. Oh, that is easy enough! An elephant is very large, and a rat is very small; a horse is neither large nor small.
Fa. Before we go any farther look what is settled on the skirt of your coat.
Ch. It is a butterfly: what a prodigiously large one! I never saw such a one before.
Fa. Is it larger than a rat, think you?
Ch. No, that it is not.
Fa. Yet you called the butterfly large, and you called the rat small.
Ch. It is very large for a butterfly.
Fa. It is so. You see, therefore, that large and small are relative terms.
Ch. I do not well understand that phrase.
Fa. It means that they have no precise and determinate signification in themselves, but are applied differently according to the other ideas which you join with them, and the different positions in which you view them. This butterfly, therefore, is large, compared with those of its own species, and small compared with many other species of animals. Besides, there is no circumstance which varies more than the size of individuals. If you were to give an idea of a horse from its size, you would certainly say it was much bigger than a dog; yet if you take the smallest Shetland horse, and the largest Irish greyhound, you will find them very much upon a par; size, therefore, is not a circumstance by which you can accurately distinguish one animal from another; nor yet is colour.
Ch. No; there are black horses, and bay, and white, and pied.
Fa. But you have not seen that variety of colours in a hare for instance.
Ch. No, a hare is always brown.
Fa. Yet if you were to depend upon that circumstance, you would not convey the idea of a hare to a mountaineer, or an inhabitant of Siberia; for he sees them white as snow. We must, therefore find out some circumstances that do not change like size and colour, and I may add shape, though they are not so obvious, nor perhaps so striking. Look at the feet of quadrupeds; are they all alike?
Ch. No: some have long taper claws, and some have thick clumsy feet without claws.
Fa. The thick feet are horny: are they not?
Ch. Yes, I recollect they are called hoofs.
Fa. And the feet that are not covered with horn and are divided into claws, are called digitated, from digitus, a finger; because they are parted like fingers. Here, then, we have one grand division of quadrupeds into hoofed and digitated. Of which division is the horse?
Ch. He is hoofed.
Fa. There are a great many different kinds of horses; did you ever know one that was not hoofed?
Ch. No, never.
Fa. Do you think we run any hazard of a stranger telling us, “Sir, horses are hoofed indeed in your country; but in mine, which is in a different climate, and where we feed them differently, they have claws?”
Ch. No, I dare say not.
Fa. Then we have got something to our purpose; a circumstance easily marked, which always belongs to the animal, under every variation of situation or treatment. But an ox is hoofed, and so is a sheep; we must distinguish still farther. You have often stood by, I suppose, while the smith was shoeing a horse. What kind of a hoof has he?
Ch. It is round and all in one piece.
Fa. And is that of an ox so?
Ch. No, it is divided.
Fa. A horse, then, is not only hoofed but whole-hoofed. Now how many quadrupeds do you think there are in the world that are whole-hoofed?
Ch. Indeed I do not know.
Fa. There are, among all animals that we are acquainted with, either in this country or in any other, only the horse, the ass, and the zebra, which is a species of the wild ass. Now, therefore, you see we have nearly accomplished our purpose; we have only to distinguish him from the ass.
Ch. That is easily done, I believe; I should be sorry if any body could mistake my little horse for an ass.
Fa. It is not so easy, however, as you imagine; the eye readily distinguishes them by the air and general appearance, but naturalists have been rather puzzled to fix upon any specific difference, which may serve the purpose of a definition. Some have, therefore, fixed upon the ears, others on the mane and tail. What kind of ears has an ass?
Ch. Oh, very long clumsy ears! Asses’ ears are always laughed at.
Fa. And the horse?
Ch. The horse has small ears, nicely turned and upright.
Fa. And the mane, is there no difference there?
Ch. The horse has a fine long flowing mane; the ass has hardly any.
Fa. And the tail: is it not fuller of hair in the horse than in the ass?
Ch. Yes; the ass has only a few long hairs at the end of the tail; but the horse has a long bushy tail when it is not cut.
Fa. Which, by the way, it is a pity it ever should. Now, then, observe what particulars we have got. A horse is an animal of the quadruped kind, whole-hoofed, with short erect ears, a flowing mane, and a tail covered in every part with long hairs. Now is there any other animal, think you, in the world, that answers these particulars?
Ch. I do not know; this does not tell us a great deal about him.
Fa. And yet it tells us enough to distinguish him from all the different tribes of the creation which we are acquainted with in any part of the earth. Do you know now what we have been making?
Ch. What?
Fa. A Definition. It is the business of a definition to distinguish precisely the thing defined from any other thing, and to do it in as few terms as possible. Its object is to separate the subject of definition, first from those with which it has only a general resemblance, then, from those which agree with it in a greater variety of particulars; and so on till by constantly throwing out all which have not the qualities we have taken notice of, we come at length to the individual or the species we wish to ascertain. It is a kind of chase, and resembles the manner of hunting in some countries, where they first enclose a large circle with their dogs, nets, and horses; and then, by degrees, draw their toils closer and closer, driving their game before them till it is at length brought into so narrow a compass that the sportsmen have nothing to do but to knock down their prey.
Ch. Just as we have been hunting this horse, till at last we held him fast by his ears and tail.
Fa. I should observe to you, that in the definition naturalists give of a horse it is generally mentioned that he has six cutting teeth in each jaw; because this circumstance of the teeth has been found a very convenient one for characterizing large classes: but as it is not absolutely necessary here, I have omitted it; a definition being the most perfect the fewer particulars you make use of, provided you can say with certainty from those particulars the object so characterized must be this and no other whatever.
Ch. But, papa, if I had never seen a horse, I should not know what kind of animal it was by this definition.
Fa. Let us hear, then, how you would give me an idea of a horse.
Ch. I would say it was a fine large prancing creature with slender legs and an arched neck, and a sleek, smooth skin, and a tail that sweeps the ground, and that he snorts and neighs very loud, and tosses his head, and runs as swift as the wind.
Fa. I think you learned some verses upon the horse in your last lesson? Repeat them.
Ch.
The wanton courser thus with reins unbound
Breaks from his stall, and beats the trembling ground;
Pamper’d and proud, he seeks the wonted tides,
And laves, in height of blood, his shining sides
His head, now freed, he tosses to the skies;
His mane dishevell’d o’er his shoulders flies;
He snuffs the females in the distant plain,
And springs, exulting, to his fields again.—Pope’s Homer.
Fa. You have said very well; but this is not a definition, it is a description.
Ch. What is the difference?
Fa. A description is intended to give you a lively picture of an object, as if you saw it; it ought to be very full. A definition gives no picture to those who have not seen it: it rather tells you what its subject is not, than what it is, by giving you such clear specific marks, that it shall not be possible to confound it with anything else; and hence it is of the greatest use in throwing things into classes. We have a great many beautiful descriptions from ancient authors so loosely worded that we cannot certainly tell what animals are meant by them: whereas, if they had given us definitions, three lines would have ascertained their meaning.
Ch. I like a description best, papa.
Fa. Perhaps so; I believe I should have done the same at your age. Remember, however, that nothing is more useful than to learn to form ideas with precision, and to express them with accuracy; I have not given you a definition to teach you what a horse is, but to teach you to think.