normal mental process. (This is a slightly different use of the word autochthonous than the ordinary medical or sociological use as a synonym for indigenous.) Secondary delusions, on the other hand, he defined as those influenced by the person's background, current situation or mental state.

Jaspers considered primary delusions to be ultimately "un-understandable" since he believed no coherent reasoning process existed behind their formation. This view has caused some controversy, and the likes of R. D. Laing