G. Spencer-Brown's arithmetic of consciousness

The article presents a short review of ideas of G. Spencer-Brown - the British logician, mathematician and philosopher, the author of the original theory of calculation of indications providing a basis for the imagined or dual logic, considering a duality and self-reference character of human knowledge. In addition, questions of manifestation of observable and not observable are considered in connection with Spencer-Brown's ideas. The comparative analysis of “arithmetic of consciousness” of Spencer-Brown and Boolean algebra is carried out. An ontological asymmetry of logic of Aristotle and its overcoming by means of algebra and Spencer-Brown's arithmetic is shown on examples. Based on the laws of form, two classes of phenomena, and accordingly, the related concepts that are relevant to answering the questions: “what is happening”? and “what is hidden behind this?” are demonstrated. The role of calculation of indications, as mathematical apparatus for modeling of cognitive processes is shown.