There are two ways to be fooled. One is to believe what isn't true; the other is to refuse to believe what is true.

The saying distinguishes two symmetrical forms of deception: credulity (assenting to falsehood) and denial (withholding assent from truth). It implies that error is not only a matter of being misled by others, but also a self-protective choice—refusing inconvenient realities, evidence, or moral demands. Framed this way, “being fooled” includes both gullibility and willful blindness. The thought resonates with Kierkegaardian concerns about subjectivity, self-deception, and the ways individuals evade truth that would require existential change; however, without a verified Kierkegaard source, it is best read as a general aphorism about epistemic responsibility rather than a securely grounded statement of his doctrine.