We discuss here what we feel could be an improvement in future discussions of the brain acting as a Bayesian-Laplacian system, by distinguishing between two classes of priors on which the brain's inferential systems operate. In one category are biological priors (β priors) and in the other artefactual ones (α priors). We argue that β priors are inherited or acquired very rapidly after birth and are much more resistant to varying experiences than α priors which, being continuously acquired at various stages throughout post-natal life, are much more accommodating of, and hospitable to, new experiences. Consequently, the posteriors generated from the two sets of priors are likewise different, being more constrained (i.e., precise) for β than for α priors
