contemplate vs reflect on

contemplate

verb
  • To look at on all sides or in all its aspects; to view or consider with continued attention; to regard with deliberate care; to meditate on; to study, ponder, or consider. 

  • To consider as a possibility. 

reflect on

verb
  • To think carefully about (something), and give it due consideration. 

  • To give an impression of (used with an adverb). 

  • To access details of (a data type, etc.) at run-time using reflection. 

How often have the words contemplate and reflect on occurred in a corpus of books? (source: Google Ngram Viewer )