We have seen that the central theme of Schopenhauer's philosophical system is that the fundamental reality is Will. Schopenhauer equates this Will with Kant's thing-in-itself. We have also seen that Kant argued that we could never know the thing-in-itself. Schopenhauer differed with Kant at this point. He argued to the contrary, that we could immediately know the thing-in-itself through the experience of an inner, volitional reality within one's own body.
Further, while he argued that Reality is comprised of oneness, as previously stated Schopenhauer acknowledged "differentness." He proposed that if we analyze this world of phenomena we might derive from it clues which point to the underlying reality of oneness which he designated as "pneumena", a term which he borrowed from Kant.
As previously stated, Schopenhauer argued that we have access to knowledge of reality not by observing the external world of objects, but rather by looking within. In this sense, Schopenhauer anticipated the work of Freud, which is a reflection of Schopenhauer's contribution to the history of thought. Though it seems Schopenhauer fails to receive credit for these types of contribution, his thought is significant.
Yet Schopenhauer was quick to acknowledge that this knowledge of reality that is gained by looking within was still a superficial knowledge. In no way is this knowledge complete. Once again, it is in this respect that Schopenhauer's work reflected the later work of Freud. Freud also argued that much of self-knowledge is unconscious and indeed the task of the psychotherapeutic process was to reveal the unconscious realities that lie beneath the surface of the human psyche.
In addition, Schopenhauer contended that this knowledge is of a dual form by which he meant that this knowledge is reflective of the subject/object dichotomy. In other words, this inner knowledge requires both the subject who knows and the object that is known, the knower and the known, or the perceiver and the perceived. This inner knowledge remains within the context of human experience.
Schopenhauer proposed that there is something about this inner experience and this effort at introspection that gives us a clue to the nature of Ultimate Reality. For example, according to Schopenhauer's thought, bodily movements are expressions of "desire" or "Will" as Schopenhauer put it. If I choose to move my arm then "I will to move my arm." The volition is the inside of the movement and the physical movement is the outside of the movement. The unconscious motivation gives us the idea of a reality as a below consciousness drive. It was this drive, which existed beneath the surface, which Schopenhauer designated as Will, Force, or Energy as we might call it today.
In short, Schopenhauer concluded that the will is an unconscious striving for personal existence or personal assertion.
