§ 6.—In relation to the realities of nature which are not external of us, language possesses no signification but as it refers to our internal experience.

To experience the recollection of a flash of lightning will tell you only what the word memory names. You may say that you wish to know how memory is caused, and what constitutes its nature. Recur, then, again, to your consciousness. Experience all which you can in relation to memory, and receive the experience as the only answer which the questions admit. If experience will not answer the questions, language cannot; for language possesses no signification in the premises, except what it derives from its reference to your experience

§ 7.—Questions are insignificant when they seek what con sciousness cannot answer.

We can answer every question which inquires after any thing that we can experience, either by our senses or our consciousness; but a question which inquires after none of these is an inquiry after nothing. How would memory look if we could see it? How would it feel, taste, smell, or sound? Does it die, or continue to live in the soul after the death of the body? If it is a property of the soul, why does it decay in old men? If it is a property of matter, is it confined to a particular piece? Does it possess gender and number? We may form as many such questions as we can form syntactical sentences; but the questions are like a numerical sum whose figures refer to nothing. The figures may be multiplied, divided, added, and subtracted, according to the rules which figures obey; but if the figures possess no ulterior reference, their product will possess no ulterior signification. Our questions also may be subjected to all the rules of logick that are applicable to the words; but so long as the words possess no ulterior reference, the answers which may be elaborated from them will possess no ulterior signification.

LECTURE XXI.

INQUIRIES AFTER A THEORY WE MISTAKE FOR AN INVESTIGATION OF NATURE.

§ 1.-The words cause and effect are, like all other words, insignificant when they refer to nothing; and are never sensibly significant of any thing but the sensible particulars to which they refer.

WHEN We disengage from our grasp a stone, and see it fall to the earth, we inquire into the cause of its descent. The inquiry is proper, but we can know nothing of the external universe except what our senses disclose; hence we must seek a sensible cause. This, however, is not our practice. We invent a verbal cause which we confound with the sensible realities of the external universe. The verbal cause is created by attributing to the stone and its descent some agent that we know to possess (were it present) the power to produce the descent. We discover in magnets a power to attract iron; hence, by attributing attraction to the earth, we make the descent of the stone congruous to our notions of causation. Nearly every movement of our body, and every volition of our mind, causes a sensible effect. We are conceived, born, and we die, by a sensible process of cause and effect. All our business, cares, and pleasures, are a combination of causes and effects. We need not wonder, therefore, that men are usually unconscious that cause and effect are only certain discoverable relations; and that where the relations are undiscoverable, the words cause and effect can be applied with no more propriety than we can apply the word elephant where no quadruped is discoverable.

$2.-To invent a verbal cause that will make a unique operation of nature, congruous to operations with which we are familiar, is mistaken for a physical discovery.

"The little bodies which compose water are," says Locke, "so loose from one another, that the least force separates them. Nay, if we consider their perpetual motion, they possess no cohesion. But let a sharp cold come, and they will unite and not be separated without great force. He that could make known the cement that makes them adhere so closely, would discover a great secret."

§ 3.-Nothing is easier than to discover the cement if it refers to any sensible information. We may examine water, and note all the information which it can yield our senses in its transformation into ice. But this was not what Locke was seeking. He wanted a theory that would make the transformation of water into ice, analogous to some of our accustomed operations. This, however, was not seeking for any thing that exists in the external universe, but for a process of words.

4.-Verbal causes may be predicated in infinitum; hence, they are characteristically distinguished from the realities of nature.

Admit that a philosopher shall say he has discovered the cement which holds frozen water in solidity. "Then," continues Locke, "this discovery aids us very little without he can discover the bonds which hold together the cement." Grant that the philosopher shall discover these also. "This will not avail," says Locke, "unless he can discover the cement which holds together the particles of the bonds;" and thus he must proceed without end: for every cement must be composed of parts which, equally with the first, will require to be cemented. If any person chooses to divert himself by constructing such speculations, I entertain no objection; but let us not confound them with the sensible realities of the external universe. When we seek causes, we must seek a sensible

existence; and where none is discoverable, we must be content to note the deficiency as part of our sensible knowledge.

§ 5.-The verbal causes which a theorist adopts are usually selected with a reference to his own occupations.

When the fabled inhabitants of a besieged city consulted as to the best means of defence, the masons recommended ramparts of stone, a carpenter recommended that they should be made of wood, and the tanners thought leather preferable. So, if you examine the various theories of philosophers, you will generally be able to divine the science with whose phenomena the philosopher is familiar. If the formation of rocks is to be accounted for by a chemist, they are caused by a chemical precipitation among the waters of a flood, by crystallizations, and by chemical combinations. If a physician becomes geologist, the interiour of the earth suffers convulsions; volcanoes vomit up rocks, and the ocean fractures them into smaller stones. If such speculations can subserve any useful purpose, I would not reject the benefit in contempt of the machinery; but that such speculations should be mistaken for the realities of nature is as curious an errour as human weakness ever exhibited.

§ 6. We must discriminate between inquiries after a theory, and inquiries after the realities of creation.

To inquire sensibly into the structure of the earth is to record all which our senses can discover. To inquire verbally is to select from our experience, and apply to the earth, such agents as we have found competent, in other cases, to produce and arrange rocks, or something analogous to rocks.

§ 7.-Natural operations which are peculiar, we find difficult to subject to a theory.

We are perplexed when we attempt to account verbally for the generation of animal life, or for any other operation to which our sensible experience furnishes no analogous operation. If the embryo animal can be deemed the production of either

an egg or a seed, we are satisfied. These are accordingly one theory. Animalculæ áre said to be discoverable in certain seminal fluids; and as we are familiar with the growth of ani mals from small to large, we can easily account for the large if we can assume the small; hence, animalculæ are another theory of generation.

§ 8.-But out of what was the first material object created? This is the most perplexing question that theory undertakes to answer. All the creative operations which we experience proceed from some material. An animal requires an egg; a tree requires a seed; but the first matter could proceed from neither egg nor seed; hence, we must either admit that matter is without a beginning, or we must produce the first matter without egg, seed, or other material. We adopt the latter alternative. Matter was produced, we say, by the fiat of Deity. We know not how; or, in other words, we know of no analogous process, and hence can make no theory.*

§ 9. We are satisfied with the vivification of eggs, provided we can discover in the animal which produces them any thing analogous to sexual organs and sexual intercourse; but some oviparous animals present the singularity of no sexual organs.

* Inductive philosophy consists in inventing verbal causes for sensible operations. Newton's laws for philosophising are properly rules for the construction of theories:that is, rules for the finding of verbal causes. We think a cause must exist, hence we see not the absurdity of attributing verbal causes. Cause and effect are, however, mere words. Nothing gives them significancy but our expe rience. Why, then, should not our experience be permitted to teach us that causes are not universal? An uneducated Ethiopian believes fluidity to be inseparable from water; but experience teaches us that the Ethiopian is mistaken. We gain nothing but delusion when we will not limit our knowledge by the revelations of nature. The relation of cause and effect is like the relation of fluidity and water. Both relations exist where we discover them to exist, and they exist not where we discover that they exist not. Air is, I believe, the only substance which presents to us tangibility without visibility. Had we not this example, we should deem visibility inseparable from tangibility. We should be correct, also, in such a belief; for the universality of the position would signify our experience only. But can any thing exist without a cause? The question is insignificant except as it refers to our experience, and no answer is sensibly significant beyond what we experience. To reject a negative instance is as fallacious as to reject an affirmative instance. Our knowledge of the realities of the universe cannot be extended beyond our sensible experience.