Now, what is true in respect to mathematics, is true in respect to every other subject that may come before the mind. There are conscious affirmations of the soul lying at the basis of all investigation; and in these conscious affirmations of the soul is to be found the standard by which to try the truth of whatever plane or sphere of thought. The first point to be taken is to ascertain what are the affirmations of the soul upon these points to be investigated. Our next step is to fix upon certain definitions, so that we can always understand precisely what we mean in our use of terms. Then we must see next that the relation between premises and conclusion be always inevitable. There must never be left any opportunity for the premises to be true and the conclusion false. Then we shall always be certain of having the truth. In investigating the science of mind and spirit, I propose to pursue this mathematical course; and not attempt to argue any point that is not capable of demonstration—that is not based upon the absolute affirmation of the soul, conducted with reference to strict definitions, and making the relation of premises and conclusion inevitable. The reason of being thus particular is, that the greatest confusion prevails, not only in respect to the subject of the New Philosophy, or Spiritualism, but in respect to all subjects pertaining to spiritual life. Man does not know precisely where to begin his investigation. He does not seem to know precisely where he is certain of any thing pertaining to spiritual existence, and thinks that it must be all conjectural. Now here is an affirmation which I believe every man in the audience will agree to be an affirmation of every one’s consciousness, and that it lies at the basis of all our investigation of this and every other subject. (I will say further, that, if any individual in the audience disagrees with me, he will confer a favor by manifesting that disagreement at any time; because I wish to be exceedingly near to you as a lecturer, and wish you to be exceedingly near to me, so that there may be the most perfect freedom of intercourse of thought and expression between us.) Then the first affirmation of the consciousness is this: That the mind can perceive nothing but its own consciousness, and that which is inwrought into that consciousness.