a priori vs plain to see

a priori

adj
  • Self-evident, intuitively obvious. 

  • Presumed without analysis. 

  • Based on hypothesis and theory rather than experiment or empirical evidence. 

  • Developed entirely from scratch, without deriving it from existing languages. 

adv
  • In a way based on theoretical deduction rather than empirical observation. 

plain to see

adj
  • evident, obvious 

How often have the words a priori and plain to see occurred in a corpus of books? (source: Google Ngram Viewer )