Complex sentence: "The Tyger" presents a duality between aesthetic beauty and primal ferocity, and Blake believes that to see one, the hand that created "The Lamb", one must also see the other, the hand that created "The Tyger".
Split into simpler sentences: The Tyger presents a duality between aesthetic beauty and primal ferocity. The speaker wonders whether the hand that created "The Lamb"also created "The Tyger".