Although usually associated with psychotic illness such as schizophrenia, the phenomena of formal and contentual thought disorder are actually rather common even among individuals not normally considered to be disturbed. Bleuler complained about the "autistic-undisciplined way of thought" (autistisch-undiszipliniertes Denken) of his fellow scientists, and Maher has more recently stressed the point that "deluded patients are like normal people — including scientists — who seem extremely resistant to giving up their preferred theories even in the face of damningly negative evidence" (Maher 1988, p. 22)