Below is an overview of a paper I wrote in 2012 on a possible way that consciousness could act to affect physical matter. A link to the paper is given at the bottom of the page.
It isn’t known how consciousness actually produces physical effects. But the paper makes several very simple assumptions and shows how consciousness would act if it followed those assumptions.
It is not known whether we have free will, i.e., whether our experience of it produces any physical change in the brain. However, there is considerable evidence for psychokinesis (PK) in laboratory experiments, such as by affecting the output of a random number generator. So I will assume that consciousness is able to act on matter using both PK and free will and that it produces its physical effects in basically the same way in these. (We should note that large-scale PK phenomena, such as poltergeist and seance phenomena, are also known to occur. However, these seem to need special conditions to be produced, and the analysis of this paper refers only to laboratory (small-scale) PK.)
The paper points out that because energy is conserved in purely physical interactions, any physical changes due to the action of consciousness cannot incur any increase or decrease in energy, with the exception that changes can be made within the limits of the uncertainty principle. We will use this latter conclusion as the basis for a model of how consciousness acts on matter. Specifically, we will assume that all physical changes directly produced by consciousness take place within the limits of the uncertainty principle, with any further changes produced through purely physical interactions resulting from these direct changes.
The paper then shows that, according to the above model, effective physical change can be produced at the molecular level, through making changes in the parameters describing the trajectories of individual molecules, within the limits of the uncertainty principle. The change in any given molecule would be small, but could be magnified through its subsequent interactions with other molecules. For instance, the action of consciousness could change the direction of a freely traveling molecule by a small amount, and later interaction with another molecule could magnify the change, so that it would travel in a substantially different direction.
We conclude that in this model consciousness can act to produce macroscopic effects if the very small changes it produces take place in an environment in which those changes can be magnified through subsequent ordinary physical interactions. (Several layers of multiplying effects might be needed.) For instance, a random number generator fulfills this description because it is able to base its macroscopic output on quantum level fluctuations. In a similar vein, in the brain an action potential is ordinarily initiated in neuronal membrane when a few ion gates are opened in an electrochemical process. Once this process is initiated, the electrochemical gradient thereby generated continues it until all necessary ion gates are opened. The latter process is entirely physical. However, it is also possible for consciousness to initiate an action potential because (as shown by calculation) it can change the direction of thermally traveling water molecules in the intercellular medium such that they travel to the ion gates and break the chemical bonds holding them closed.
The number of molecules consciousness must act on to initiate an action potential can be calculated: It takes the impact of 80 water molecules, moving at thermal velocity, to break a chemical bond. Several bonds must be broken to open an ion gate, and several gates must be opened to initiate an action potential. It is estimated that about 2,000 molecules are needed to produce this result.
We note that energy is conserved in the above process, with no expenditure of energy by consciousness, aside from negligible amounts within the limits of the uncertainty principle when consciousness starts the process. The water molecules are originally traveling in random directions, and through the action of consciousness their direction is changed so they are now traveling toward an ion gate. They are traveling at thermal energy, and it is part of that energy that is used to break the chemical bonds.
However, in the above process, the disordered energy of molecules moving thermally (heat) is transformed into the ordered energy of molecules all moving in the same direction, i.e., that can do work, with no other change. Therefore, because of its ability to change disordered motion into ordered motion, the action of consciousness can be viewed as violating the second law of thermodynamics. Alternatively, it can be viewed as providing an extension to the second law, that shows how consciousness interacts with matter.
Burns, J. E. (2012), The action of consciousness and the uncertainty principle. Journal of Nonlocality, 1(1). http://journals.sfu.ca/jnonlocality/index.php/jnonlocality/article/view/9.