Because the Green Lady is sinless, she’s able to communicate directly with Maleldil through her thoughts and perceptions. Ransom can’t; for him, communication with Maleldil often takes the more cumbersome form of a heavy, irresistible presence. The Lady’s explanation references Christian theology—because God became human in Jesus Christ, any creature possessing a rational nature (made, in other words, in the image of God) will now also take a human, or human-like, form. This might be an indirect critique of H. G. Wells—while Wells’s science fiction suggests that humanity’s position in the universe is because of humans’ inherent superiority, Lewis argues that it’s because the human form imitates God.