who came up with the theory of crystallized vs fluid intelligence
Fluid and crystallized intelligence Fluid and crystallized intelligence were originally identified by Raymond Cattell.[3] Concepts of fluid and crystallized intelligence were further developed by Cattell's student, John L. Horn. Since Cattell's and Horn's publications, the concepts of fluid and crystallized intelligence have become so ingrained in the field of intelligence that they are no longer routinely attributed to Cattell or Hornâ€”much as Cattell's scree plot became ingrained in the practice of factor analysis or Freud's concept of the subconscious is ingrained in psychology and in the public's perceptions of the mind.
Mind–body dualism Dualism is closely associated with the thought of René Descartes (1641), which holds that the mind is a nonphysical—and therefore, non-spatial—substance. Descartes clearly identified the mind with consciousness and self-awareness and distinguished this from the brain as the seat of intelligence.[6] Hence, he was the first to formulate the mind–body problem in the form in which it exists today.[7] Dualism is contrasted with various kinds of monism. Substance dualism is contrasted with all forms of materialism, but property dualism may be considered a form of emergent materialism or non-reductive physicalism in some sense.