Abstract Two striking claims are advanced on behalf of the free energy principle (FEP) in cognitive science and philosophy: (i) that it identifies a condition possibility existence for self-organising systems; (ii) has important implications our understanding how brain works, defining set process theories—roughly, theories structure functions neural mechanisms—consistent with minimising imperat...

χ2 minimisation. The determination of parameters in fits to measured data is a standard task of data analysis. The standard method of least squares is often referred to as χ2 minimisation, which is a confusion in terminology; the minimum of the least squares sum follows often, but not always, the χ2 distribution. In “χ2 minimization” used in a wide range of applications from calorimeter calibra...

In his 1985 article (“Projection pursuit”), Huber demonstrates the interest of his method to estimate a density from a data set in a simple given case. He considers the factorization of density through a Gaussian component and some residual density. Huber’s work is based on maximizing Kullback–Leibler divergence. Our proposal leads to a new algorithm. Furthermore, we will also consider the case...