Classical unified field theories describe the properties of the electromagnetic field as a purely geometric phenomenon. Einstein tried to form a generalized theory of gravitation that would unify the gravitational and electromagnetic forces (and perhaps others), guided by a belief in a single origin for the entire set of physical laws. These attempts initially concentrated on additional geometric notions such as vierbeins and "distant parallelism", but eventually centered around treating both the metric tensor and the affine connection as fundamental fields. (Because they are not independent, the metric-affine theory was somewhat complicated.) In general relativity, these fields are symmetric (in the matrix sense), but
Unified Theories of Cognition a mind does the following: Newell's secondary task is to put forward the cognitive architecture Soar as an implementation of a UTC that meets the constraints above. Other efforts at unified theories of cognition cited in the book include ACT-R and the human processor model. Unified Theories of Cognition Unified Theories of Cognition is a 1990 book by Allen Newell. Newell argues for the need of a set of general assumptions for cognitive models that account for all of cognition: a unified theory of cognition, or cognitive architecture. Newell argues that the mind functions as a single system. He also