Figure 8.
Generic two-system interaction mediated by a Markov blanket. (a) Any MB can be considered a boundary B in the joint state space of a system S and its environment E. The physical interaction between S and E, here represented by the Hamiltonian (total energy) operator HSE, is defined at this boundary. (b) S must obtain free energy from and exhaust waste heat into E. The boundary B must therefore include a thermodynamic sector in addition to the sensory (s) and active (a) sectors. The states of this thermodynamic sector are observationally inaccessible and hence uninformative to S. Taken from [78] with a CC-BY license.