attestation vs theory

attestation

noun
  • A thing that serves to bear witness, confirm, or authenticate; validation, verification, documentation. 

  • The process, performed by accountants or auditors, of providing independent opinion on published financial and other business information of a business, public agency, or other organization. 

  • A confirmation or authentication. 

  • An appearance in print or otherwise recorded on a permanent medium. 

theory

noun
  • A description of an event or system that is considered to be accurate. 

  • A coherent statement or set of ideas that explains observed facts or phenomena and correctly predicts new facts or phenomena not previously observed, or which sets out the laws and principles of something known or observed; a hypothesis confirmed by observation, experiment etc. 

  • A field of study attempting to exhaustively describe a particular class of constructs. 

  • A set of axioms together with all statements derivable from them; or, a set of statements which are deductively closed. Equivalently, a formal language plus a set of axioms (from which can then be derived theorems). The statements may be required to all be bound (i.e., to have no free variables). 

  • A hypothesis or conjecture. 

  • The underlying principles or methods of a given technical skill, art etc., as opposed to its practice. 

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