The ocean's response to this intrusion exposes the deeper, hidden aspects of the personalities of the human scientists, while revealing nothing of the ocean's nature itself. It does this by materializing physical simulacra, including human ones; Kelvin confronts memories of his dead lover and guilt about her suicide. The "guests" of the other researchers are only alluded to. All human efforts to make sense of Solaris's activities prove futile. As Lem wrote, "The peculiarity of those phenomena seems to suggest that we observe a kind of rational activity, but the meaning of this seemingly rational activity of the Solarian Ocean is beyond the reach of human beings." He also wrote that he deliberately chose to make the sentient alien an ocean to avoid any personification and the pitfalls of anthropomorphism in depicting first contact.