Note 7 — PREFACE TO THE SECOND EDITION 1787
J. M. D. (John Miller Dow) Meiklejohn translation
In order to cognize an object, I must be able to prove its possibility, either from its reality as attested by experience, or à priori, by means of reason. But I can think what I please, provided only I do not contradict myself; that is, provided my conception is a possible thought, though I may be unable to answer for the existence of a corresponding object in the sum of possibilities. But something more is required before I can attribute to such a conception objective validity, that is real possibility—the other possibility being merely logical. We are not, however, confined to theoretical sources of cognition for the means of satisfying this additional requirement, but may derive them from practical sources.