The Effect of Mind upon Brain

Abstract

A physics-based understanding of how our conscious thoughts can affect our physically described brains is presented. This understanding depends on the shift from the mechanical conception of nature that prevailed in science from the time of Isaac Newton until the dawn of the twentieth century to the psychophysical conception that emerged from the findings of Planck, Bohr, Heisenberg, and von Neumann. This shift converted the role of our conscious thoughts from that of passive observers of a causally closed physically described universe to that of active participants in an essentially psychophysical understanding of nature. 1. The Basic Question and Why It Is Important. Science’s conception of the physical world changed radically during the twentieth century. At the end of the nineteenth century most scientists still viewed the physical universe as essentially a giant machine. This mechanical view emerged from the seventeenth century work of Isaac Newton, who built his conception of nature on the ideas of Rene Descartes. According to Descartes, the universe is composed of two kinds of elements, the first consisting of elements each of which occupies at each instant of time a definite region in space, and the second consisting of elements that include our human thoughts. Descartes allowed these two parts of nature to interact causally within our brains, but Newton specified that the motions of the elements of the first kind are completely determined by laws of motion that refer exclusively to elements of this kind. In Newtonian-type physics these elements of the first kind are, moreover, essentially mechanical, in the sense that they have been stripped of the experiential qualities that characterize our thoughts, such as the conscious awareness of feelings, and the capacity to grasp meanings. Consequently there is in Newtonian-type physics no possibility for any causally effective role for any aspects of our being that are essentially different in kind from the mechanical elements that occur in that type of physics. Descartes’ views accommodated our intuitive feeling that our conscious thoughts can influence our bodily movements – my conscious intent to raise my arm seems to cause my arm to rise – whereas Newton’s physics leads to the contrary conclusion that, in spite of what may seem to be the case, the notion that human thoughts, per se, can affect human actions is a deeply misleading illusion. Newton’s ideas led eventually to the classical physics of the late nineteenth century. Its main premises are these: 2 1. There exists a material universe that develops over the course of time by means of interactions of its tiny mechanical parts with neighboring tiny mechanical parts. 2. These interactions are governed by mathematical laws. 3. These laws entail that the mechanically described future is completely determined by the mechanically described past, with no reference to human thoughts, choices, or