=Types of Consciousness.=--Although allowable, from the standpoint of the learning process, to describe a conscious state as an attitude of awareness in which the individual grasps the significance of an experience in relation to his own needs; it must be recognized that not all consciousness manifests this meaningful quality, or this relation to a felt aim, or end. While lying, for instance, in a vague, half-awake state, although one is conscious, the mental condition is quite devoid of the meaningful quality referred to, and entirely lacks the feeling of reaction, or of mental effort. In this case there is no distinct reference to the needs of the self, and a lack of that focusing of attention necessary to give the consciousness a meaning and purpose in the life of the individual. All such passive, or effortless, states of consciousness, which make up those portions of mental existence in which no definite presentation seems to hold the attention, although falling within the sphere of the scientific psychologist, may nevertheless be left out of consideration in a study of educational psychology. Learning involves apperception, and apperception is always giving a meaning to new presentations by actively bringing old knowledge to bear upon them. For the educator, therefore, psychology may be limited to a study of the definite states of consciousness which arise through an apperceiving act of attention, that is, to our states of experience and the processes connected therewith. For this reason, psychology is by some appropriately enough defined as the science of experience.
=Consciousness a Stream.=--Although we describe the data of psychology as facts, or states, of consciousness, a moment's reflection will show that our conscious life is not made up of a number of mental states, or experiences, completely separated one from the other. Our consciousness is rather a unified whole, in which seemingly disconnected states blend into one continuous flow of conscious life. For this reason, consciousness is frequently compared to a stream, or river, moving onward in an unbroken course. This stream of consciousness appears as disjointed mental states, simply because the attention discriminates within this stream, and thus in a sense detaches different portions one from the other, or, as sometimes figuratively put, it creates successive waves on the stream of consciousness. A mental state, or experience, so-called, is such a discriminated portion of this stream of consciousness, and is, therefore, itself a process, the different processes blending in a continuous succession or relation to make up the unbroken flow of conscious life. For this reason psychology is frequently described as a study of conscious processes.