⁶For neuroscience-oriented introductions, see (Kersten et al., 2004; Ma et al., 2022). While Thomas Bayes is usually credited with the general mathematical theory used in this context, the specific idea of perception as unconscious inference was actually formulated later by Hermann von Helmholtz, which is why some authors call this framework the Helmholtzian theory of perception. (Also, the credit for the mathematical theory should perhaps largely go to Pierre-Simon Laplace.) The recent proposal of a “free-energy” brain theory (Friston, 2010) is essentially a reformulation of these ideas, with some additional hypotheses extending it to action selection.