“The mind is its own place, and in itself can make a Heaven of Hell, a Hell of Heaven.”
The line gives mental interpretation enormous power, while its speaker and dramatic context also caution against treating self-deception as wisdom.
Source details
Paradise Lost (1667), Book I, lines 254–255; Satan speaks the sentence beginning ‘The mind is its own place.’ This collection retains normalized modern orthography; the scan-backed 1667 transcription reads forms including ‘in it self’ and ‘Heav’n.’ Character context matters because this is Satan’s argument, not Milton speaking autobiographically.