The Prose Works of Percy Bysshe Shelley, Vol. 1 [of 2]

by Percy Bysshe Shelley

A man knows, not only that he now is, but that there was a time when he did not exist; consequently there must have been a cause. But we can only infer, from effects, causes exactly adequate to those effects. There certainly is a generative power which is effected by particular instruments; we cannot prove that it is inherent in these instruments, nor is the contrary hypothesis capable of demonstration. We admit that the generative power is incomprehensible, but to suppose that the same effects are produced by an eternal Omnipotent and Omniscient Being, leaves the cause in the same obscurity, but renders it more incomprehensible.

We can only infer from effects causes exactly adequate to those effects. An infinite number of effects demand an infinite number of causes, nor is the philosopher justified in supposing a greater connexion or unity in the latter, than is perceptible in the former. The same energy cannot be at once the cause of the serpent and the sheep; of the blight by which the harvest is destroyed, and the sunshine by which it is matured; of the ferocious propensities by which man becomes a victim to himself, and of the accurate judgment by which his institutions are improved. The spirit of our accurate and exact philosophy is outraged by conclusions which contradict each other so glaringly.

The greatest, equally with the smallest motions of the Universe, are subjected to the rigid necessity of inevitable laws. These laws are the unknown causes of the known effects perceivable in the Universe. Their effects are the boundaries of our knowledge, their names the expressions of our ignorance. To suppose some existence beyond, or above them, is to invent a second and superfluous hypothesis to account for what has already been accounted for by the laws of motion and the properties of matter. I admit that the nature of these laws is incomprehensible, but the hypothesis of a Deity adds a gratuitous difficulty, which so far from alleviating those which it is adduced to explain, requires new hypotheses for the elucidation of its own inherent contradictions.

The laws of attraction and repulsion, desire and aversion, suffice to account for every phenomenon of the moral and physical world. A precise knowledge of the properties of any object, is alone requisite to determine its manner of action. Let the mathematician be acquainted with the weight and volume of a cannon ball, together with the degree of velocity and inclination with which it is impelled, and he will accurately delineate the course it must describe, and determine the force with which it will strike an object at a given distance. Let the influencing motive, present to the mind of any person be given, and the knowledge of his consequent conduct will result. Let the bulk and velocity of a comet be discovered, and the astronomer, by the accurate estimation of the equal and contrary actions of the centripetal and centrifugal forces, will justly predict the period of its return.

The anomalous motions of the heavenly bodies, their unequal velocities and frequent aberrations, are corrected by that gravitation by which they are caused. The illustrious Laplace has shewn that the approach of the Moon to the Earth, and the Earth to the Sun, is only a secular equation of a very long period, which has its maximum and minimum. The system of the Universe then is upheld solely by physical powers. The necessity of matter is the ruler of the world. It is vain philosophy which supposes more causes than are exactly adequate to explain the phenomena of things. Hypotheses non fingo: quicquid enim ex phænomenis non deducitur, hypothesis vocanda est; et hypotheses vel metaphysicæ, vel physicæ, vel qualitatum occultarum, seu mechanicæ, in philosophiâ locum non habent.

You assert that the construction of the animal machine, the fitness of certain animals to certain situations, the connexion between the organs of perception and that which is perceived; the relation between everything which exists, and that which tends to preserve it in its existence, imply design. It is manifest that if the eye could not see, nor the stomach digest, the human frame could not preserve its present mode of existence. It is equally certain, however, that the elements of its composition, if they did not exist in one form, must exist in another; and that the combinations which they would form, must so long as they endured, derive support for their peculiar mode of being from their fitness to the circumstances of their situation.

It by no means follows, that because a being exists, performing certain functions, he was fitted by another being to the performance of these functions. So rash a conclusion would conduct, as I have before shewn, to an absurdity; and it becomes infinitely more unwarrantable from the consideration that the known laws of matter and motion, suffice to unravel, even in the present imperfect state of moral and physical science, the majority of those difficulties which the hypothesis of a Deity was invented to explain.

Doubtless no disposition of inert matter, or matter deprived of qualities, could ever have composed an animal, a tree, or even a stone. But matter deprived of qualities, is an abstraction, concerning which it is impossible to form an idea. Matter, such as we behold it, is not inert. It is infinitely active and subtile. Light, electricity, and magnetism are fluids not surpassed by thought itself in tenuity and activity: like thought they are sometimes the cause and sometimes the effect of motion; and, distinct as they are from every other class of substances with which we are acquainted, seem to possess equal claims with thought to the unmeaning distinction of immateriality.

The laws of motion and the properties of matter suffice to account for every phenomenon, or combination of phenomena exhibited in the Universe. That certain animals exist in certain climates, results from the consentaneity of their frames to the circumstances of their situation: let these circumstances be altered to a sufficient degree, and the elements of their composition must exist in some new combination no less resulting than the former from those inevitable laws by which the Universe is governed.

It is the necessary consequence of the organization of man, that his stomach should digest his food: it inevitably results also from his gluttonous and unnatural appetite for the flesh of animals that his frame be diseased and his vigour impaired; but in neither of these cases is adaptation of means to end to be perceived. Unnatural diet, and the habits consequent upon its use are the means, and every complication of frightful disease is the end, but to assert that these means were adapted to this end by the Creator of the world, or that human caprice can avail to traverse the precautions of Omnipotence, is absurd. These are the consequences of the properties of organized matter; and it is a strange perversion of the understanding to argue that a certain sheep was created to be butchered and devoured by a certain individual of the human species, when the conformation of the latter, as is manifest to the most superficial student of comparative anatomy, classes him with those animals who feed on fruits and vegetables.[36]