We are conscious of an animal in us, which awakens in proportion as our higher nature slumbers. It is reptile and sensual, and perhaps cannot be wholly expelled; like the worms which, even in life and health, occupy our bodies. Possibly we may withdraw from it, but never change its nature. I fear that it may enjoy a certain health of its own; that we may be well, yet not pure. The other day I picked up the lower jaw of a hog, with white and sound teeth and tusks, which suggested that there was an animal health and vigor distinct from the spiritual. This creature succeeded by other means than temperance and purity. "That in which men differ from brute beasts," says Mencius, "is a thing very inconsiderable; the common herd lose it very soon; superior men preserve it carefully." Who knows what sort of life would result if we had attained to purity? If I knew so wise a man as could teach me purity I would go to seek him forthwith. "A command over our passions, and over the external senses of the body, and good acts, are declared by the Ved to be indispensable in the mind's approximation to God." Yet the spirit can for the time pervade and control every member and function of the body, and transmute what ill form is the grossest sensuality into purity and devotion. The generative energy, which, when we are loose, dissipates and makes us unclean, when we are continent invigorates and inspires us. Chastity is the flowering of man; and what are called Genius, Heroism, Holiness, and the like, are but various fruits which succeed it. Man flows at once to God when the channel of purity is open. By turns our purity inspires and our impurity casts us down. He is blessed who is assured that the animal is dying out in him day by day, and the divine being established. Perhaps there is none but has cause for shame on account of the inferior and brutish nature to which he is allied. I fear that we are such gods or demigods only as fauns and satyrs, the divine allied to beasts, the creatures of appetite, and that, to some extent, our very life is our disgrace.
"How happy's he who hath due place assigned
To his beasts and disafforested his mind!
Can use this horse, goat, wolf, and ev'ry beast,
And is not ass himself to all the rest!
Else man not only is the herd of swine,
But he's those devils too which did incline
Them to a headlong rage, and made them worse."
All sensuality is one, though it takes many forms; all purity is one. It is the same whether a man eat, or drink, or cohabit, or sleep sensually. They are but one appetite, and we only need to see a person do any one of these things to know how great a sensualist he is. The impure can neither stand nor sit with purity. When the reptile is attacked at one mouth of his burrow, he shows himself at another. If you would be chaste, you must be temperate. What is Chastity? How shall a man know if he is chaste? He shall not know it. We have heard of this virtue, but we know not what it is. We speak conformably to the rumor which we have heard. From exertion come wisdom and purity; from sloth ignorance and sensuality. In the student sensuality is a sluggish habit of mind. An unclean person is universally a slothful one, one who sits by a stove, whom the sun shines on prostrate, who reposes without being fatigued. If you would avoid uncleanness, and all the sins, work earnestly, though it be at cleaning a stable. Nature is hard to be overcome, but she must be overcome. What avails it that you are Christian, if you are not purer than the heathen, if you deny yourself no more, if you are not more religious? I know of many systems of religion esteemed heathenish whose precepts fill the reader with shame, and provoke him to new endeavors, though it be to the performance of rites merely.
I hesitate to say these things, but it is not because of the subject- I care not how obscene my words are- but because I cannot speak of them without betraying my impurity. We discourse freely without shame of one form of sensuality, and are silent about another. We are so degraded that we cannot speak simply of the necessary functions of human nature. In earlier ages, in some countries, every function was reverently spoken of and regulated by law. Nothing was too trivial for the Hindoo lawgiver, however offensive it may be to modern taste. He teaches how to eat, drink, cohabit, void excrement and urine, and the like, elevating what is mean, and does not falsely excuse himself by calling these things trifles.
Every man is the builder of a temple, called his body, to the God he worships, after a style purely his own, nor can he get off by hammering marble instead. We are all sculptors and painters, and our material is our own flesh and blood and bones. Any nobleness begins at once to refine a man's features, any meanness or sensuality to imbrute them.
Quoted from Walden, Or Life In The Woods by Henry David Thoreau (1854).