Probability Kinematics And Commutativity*

The so‐called “non‐commutativity” of probability kinematics has caused much unjustified concern. When identical learning is properly represented, namely, by identical Bayes factors rather than identical posterior probabilities, then sequential probability‐kinematical revisions behave just as they should. Our analysis is based on a variant of Field’s reformulation of probability kinematics, divested of its (inessential) physicalist gloss.