By a little reflection it will be seen that Dr. Brown's inference is entirely unfounded. "If two hundred particles existing in a certain state form a doubt," it does not necessarily follow that "the division of these into two equal aggregates of the particles," would form halves of a doubt. If two hundred pounds weight attached to a certain machine will produce a result called motion, it does not necessarily follow that one hundred pounds will produce a result called half of a motion. If exactly two hundred particles organized in a certain form, were requisite to produce a certain thought, then it is evident that to alter in the least either the number or organization would be a complete destruction of that particular thought, instead of forming fractions of it. This is what Priestley and his followers assert. They say that thought begins and ends with the organization, and that the single individuals entering into the system, form no thought nor fractions of a thought. This absurdity, therefore, remains untouched by this argument of Dr. Brown. It is effectually demolished, however, by another species of argument, used by him to which we have already referred. He has proved Priestley's theory to be false, not by supposing that the fractions of a doubt could be made to result from it, but by clearly showing that an organ is only a name for a collection of many substances, which cannot possibly possess any property as a whole, which the individuals do not possess when existing singly. He has also proved the theory which asserts that a thought or a feeling is a little particle of matter, to be false, because it involves the absurdity of fractional thoughts, hopes, fears, &c.

But there is one more theory which we venture to propose, that we believe to be impregnable, which no philosopher or metaphysician ever has or ever can refute. This theory may be stated as follows:—

A thought, hope, fear, joy, or any other feeling is not a little particle of matter, nor the result or quality of a collection of particles, called an organ or a system or organs, but it is the state or affection of a single individual substance, having extension and parts, and all the essential characteristics belonging to all other matter.

There is no absurdity in speaking of the half, or of a quarter, or of any other fractional part of this substance, but there would be a great absurdity in speaking of the fractional parts of its mere states or affections. The half or a thousandth part of a thinking substance is as reasonable as the half or a thousandth part of an attracting substance; but the top or bottom of a thought would be as absurd as the top or bottom of attraction. The north or east side of a substance which remembers, is just as correct as the north or east corners of a substance which possesses a chemical affinity; but the north side of a remembrance would be as inconsistent as the north side of a chemical affinity. Hence, none of the arguments which are so successfully brought to bear against the other two theories, will in the least affect this. It is invulnerable in every point at which it may be assailed.

Every conceivable part of this substance, however minute, possesses the same property as the whole. A thought, or any other state of feeling is, therefore, perceived by every possible part of which a whole consists. A unity of substance, as we have already had occasion to remark, consists of an immense number of fractional parts. These, in order to constitute unity, must be so closely connected with, and related to each other, that whatever state or affection one may happen to be in, all the rest must immediately be notified of the same. If one part be affected with pain, every other part most be conscious of it. If one part rejoices, hopes, or fears, the whole must, by sympathy, rejoice, hope, or fear in the same manner. But if one part could suffer, while another part was unconscious of such suffering; or if the affection of one part had no tendency to affect another, then the individual unity would be destroyed, and the substance would be as many distinct, thinking, feeling beings as there were parts unconscious of the affections of the others.

It is not necessary that a thinking substance should be limited to magnitudes or quantities that are exceedingly minute in order to constitute a unity. Large amounts of substance are as consistent with unity as small ones. But in all cases, whether the quantity be large or small, it is necessary that the parts should bear that relation to each other, that when one is affected every other should be affected also; otherwise, it could not be a unity. The feeling or thinking substance of an elephant or whale is as much an individual unity as the feeling substance or spirit of a gnat or animalculæ, though the magnitude of the former far exceeds that of the latter. It is the peculiar organization or relation of parts in such a manner as to be all conscious of each other's affection which constitutes the unity, without any regard to the size or amount of substance organized. When the several parts are so organized as to think, remember, hate, love, and feel alike, under the different circumstances to which the organization may be exposed, the whole is one individual unity or being.

If the mind or spirit be of the same magnitude as the body, then the impressions received through the various organs of a human body would only have to be transferred to the distance of about five feet, in order that every part of the mind might be alike conscious of such impressions. Let the velocity be ever so rapid, time would be an essential ingredient to the transfer of these communications from part to part. If they were communicated with the velocity of sound, those parts of the mind the most distant from the one first affected, would receive the impression in the two hundredth part of a second. If the transfer were as rapid as light, the impression would be conveyed to the most distant extremities of the mind in the two hundred millionth part of a second. These inconceivably minute portions of time would be altogether imperceptible to the mind. Hence, whenever any part of the mind is affected through its sensorial organs, every other part seems to be affected in the same instant, whereas, in reality, the affection is conveyed successively from part to part, the same as sound or light is conveyed from a sounding or a luminous body.

The conveyance of internal thoughts or emotions of any kind form one part of the mind to the other, is probably equal in velocity to the transfer of the various notions gained by sensation. Therefore, in consequence of the inconceivable velocity with which all thoughts and sensations are conveyed from one extremity of the mind to another, it is impossible for one part of the mind to have a thought, sensation, or feeling of any kind which the other parts of the mind can, during any term of time that is appreciable, be ignorant of. It is for this reason that the whole of the mind thinks,—the whole of the mind loves,—the whole of the mind hates,—the whole of the mind wills, &c.

If the term of time were of any appreciable length in which thoughts and feelings are conveyed from one part of the perceptive mind to the other, then, while one part of the mind was hating an object, another part of the same mind might be loving it because of newly discovered qualities; and while a part of the mind in one foot was suffering intense pain, caused by treading upon hot iron, another part of the mind in the other foot, not having had time to receive the information, would venture also into the same danger.

Were it possible for the different parts of the mind to feel and think without being able to communicate their respective feelings to each other, then every part that thus thought and felt, would be a distinct individual, as much so as if it were separated for miles from all the rest, or, as if it were a separate organization. In this case, the whole being or mind which we before termed I, would cease its individual unity; and each part which thought and felt independently, could appropriate to itself the term I, and with the greatest propriety could apply the term YOU to every other part which thought and felt distinctly and differently from itself.