E. Cobham Brewer 18101897. Dictionary of Phrase and Fable. 1898.
according to what is supposed or assumed.
The justification of the charge [i.e. the tax for betterment] lies ex hypothesi in an enhanced value of the property in the Betterment area.The Property Protection objection against section 37 of the Betterment clause of the Tower Bridge Southern Approach Bill (1894).