The subconscious is available to us through hypnosis, meditation, dreams, and other methods. It motivates many of our actions, even if we think we are acting in full consciousness. It is in the background of our lives, like the submerged part of the iceberg.
The unconscious is what existed before the subconscious came into being but it is still you. It is before you were in your mother’s womb. It is pre-thought and ever-existing. It has nothing to do with the mind, the brain, language, human experience, or anything else we can conceive of. It is the Universe within but it is not aware of itself.
Like the subconscious mind, it too, is available to us. While the subconscious brings some drama of past lives and repressed memories of this life, the Unconscious state can bring deep peace. The path is through spiritual contemplation, meditation, yoga, and the pointers of mystical beings. It can never be described in words and is blessedly, eternally dark.