Stylistic evidence and laboratory evidence strongly support the claim that the magnificent painting Garden of Eden is a work of the Flemish master van Eyck  Nevertheless, the painting must have been the work of someone else, as any one with a little historical and zoological knowledge can tell merely by looking at the painting  The animals in the painting are all vivid representations of actual animals, including armadillos
Yet armadillos are native only to the Americas, and van Eyck died decades before Europeans reached the Americas
The first is a judgment that serves as the basis for the main conclusion of the argument; the second states that main conclusion.