The Tortoise then asks Achilles whether a second kind of reader might exist, who accepts that "A" and "B" are true, but who does "not" yet accept the principle that "if" "A" and "B" are both true, "then" "Z" must be true. Achilles grants the Tortoise that this second kind of reader might also exist. The Tortoise, then, asks Achilles to treat the Tortoise as a reader of this second kind. Achilles must now logically compel the Tortoise to accept that "Z" must be true. (The tortoise is a reader who denies the argument form itself; the syllogism's conclusion, structure, or validity.)