hypothesis vs mental picture

hypothesis

noun
  • An assumption taken to be true for the purpose of argument or investigation. 

  • Used loosely, a tentative conjecture explaining an observation, phenomenon or scientific problem that can be tested by further observation, investigation and/or experimentation. As a scientific term of art, see the attached quotation. Compare to theory, and quotation given there. 

  • The antecedent of a conditional statement. 

mental picture

How often have the words hypothesis and mental picture occurred in a corpus of books? (source: Google Ngram Viewer )