The next subject in order is that of clairaudience, or "clear hearing." It is a faculty of the human mind much more rarely developed than that of clairvoyance,--that is, if we assume the latter to be identical with telepathy, which we may do for the purposes of this discussion. The Century Dictionary defines clairaudience as "the supposed power of hearing in a mesmeric trance sounds which are not audible to the ear in the natural waking condition." This, as far as it goes, is a correct definition of that faculty; but it defines a very small part of its field of operations, and that part which is of the least importance. It may be defined, broadly, to be "the power of hearing the spoken words of a human soul." In other words, it is that faculty of man's intelligence which enables his objective mind to receive communications from his own subjective mind or from that of another by means of spoken words. It is one means of bringing the operations of the subjective mind above the threshold of consciousness. The power is by no means confined to persons in a mesmeric trance, although it seems probable that one must be in a partially subjective state to enable him to hear clairaudiently. The degree of subjectivity may be very slight, so that the percipient may seem to himself and others to be in a perfectly normal condition. The sounds--if that may be called sound which does not cause atmospheric vibrations--are perfectly distinct to the consciousness of the percipient, but are not perceptible to others who may be near him and in the normal condition. Like all other means for bringing the operations of the subjective mind above the threshold of consciousness, the sounds have from time immemorial been attributed to supernatural agencies. Socrates furnished the most notable example in ancient or modern times of a man whose subjective mind was able at any time to communicate messages to his objective mind by means of spoken words. It is well known that he supposed himself to be constantly attended by a dæmon, or guardian spirit, who watched over him and warned him of any danger that was imminent. (See Chapter X. for a fuller discussion of Socrates and his dæmon.) The biblical student will recall to mind many instances where voices were heard, conveying intelligence of the most portentous character, and a critical examination of some of the instances will not fail to reveal their true nature.