Out of the Silent Planet depicts the cosmic significance of the individual's choices, the evils of social engineering, the absurdity of racism, and the limitations of man's appropriate power without mentioning any of these words. Lewis presents a Pedestrian, a vacationing don named Ransom, whose everyman title and mixed motives make him believable. His decent responses to the alien good and the familiar evil engage the reader's sympathy. For example, when Ransom acts as a translator for the evil scientist's plans for the universe by placing Weston's bombastic scientism in words prelapsarian creatures can understand, Lewis is able to strip bare the ultimate banality of the evil implicit in these plans.

In this novel, then, Lewis indicts those modern movements which have resulted in pogroms, concentration camps, total war, and totalitarianism: social Darwinism, militant materialism, moral relativism. Against the reduction of human beings to integers arrangeable at the whim of scientistic rulers, Lewis presents man's supernatural nature and destiny, his being part of a creation of love and freedom. In his coining the word hnau to mean all rational creatures regardless of their morphology, Lewis affirms the absolute dignity of humankind regardless of race, nationality, or limitations.