At the level of any individual sales transaction, mercantilism held that profit was developed at the point of the sale. Steuart held that profit was a mere "surcharge" upon alienation (sale) of the commodity. Steuart was not a pure mercantilist, however, he believed in a "scientific form of mercantilism." Steuart held that all profit arose from the seller "overcharging" the buyer in any single sales transaction. However, Steuart did allow that the "profit" obtained through exchange would "fluctuate" with the rise and/or fall in demand. Still like all good mercantilists, Steuart's eye remained on the exchange as the creator of profit and he recognized no value in a commodity before the sale.