By deduction; by way of inference; by consequence.

By way of necessary inference.

You might say that genius works inductively and finds a method; the conservative works deductively from the method and defeats whatever genius he may have. – A Preface to Politics by Walter Lippmann

The false induction from genuine facts of observation, leading to the construction of theories which are then deductively applied in the face of the results of direct observation. – The Complete PG Works of Oliver Wendell Holmes, Sr. by Oliver Wendell Holmes, Sr. (The Physician and Poet not the Jurist)