  From the lack of any form of similitude or affinity between object/sensation, and sensation/idea, it follows that there is no such relation which holds between an idea and an external (material) object. From this lack of similitude, Le Grand concluded that adventitious ideas (coming from material objects outside us) must be innate or inbred in the mind. For, if the external object is not like the idea we form of it, then the only explanation remaining is that the mind is responsible for it. Likewise, fictitious ideas, like sirens and chimeras, have no exemplar outside the mind and so must be formed according to forms natural to the human mind. And finally, common notions such as substance, truth, goodness, equity, and God, as well as axioms such as the same thing cannot be and not be, are innate, that is, they proceed from the mind alone, since all corporeal motions are particular but these notions are universal. The sense in which they are innate differs from adventitious and fictitious ideas; innate ideas do not proceed from the senses or the imagination but “are congenite and inbred with the said mind, from their original” (1694, p. 328). By this Le Grand meant that the mind or thought itself, not any of its faculties such as sense or intellection, is the principle or original of such ideas. These ideas are formed in the mind by the mind and from the mind.