Before revision:  In particular, in addition to highlighting the implicit restriction to linear models, we identify three formal errors in the main argument of Friston (2013): The first concerns the rewriting of the  equations of motion of systems with Markov blankets which turns out not to be generally correct .
After revision:  In particular, in addition to highlighting the implicit restriction to linear models, we identify three formal errors in the main argument of Friston (2013): The first concerns the rewriting of the equations of motion of systems with Markov blankets , are not generally correct without additional (previously unstated) assumptions .