Hume accepts that ideas may be either the product of mere sensation or of the imagination working in conjunction with sensation. According to Hume, the creative faculty makes use of (at least) four mental operations that produce imaginings out of sense-impressions. These operations are "compounding" (or the addition of one idea onto another, such as a horn on a horse to create a unicorn); "transposing" (or the substitution of one part of a thing with the part from another, such as with the body of a man upon a horse to make a centaur); "augmenting" (as with the case of a giant, whose size has been augmented); and "diminishing" (as with Lilliputians, whose size has been diminished). (Hume 1974:317) In a later chapter, he also mentions the operations of "mixing", "separating", and "dividing". (Hume 1974:340)