A paradox is defined as a statement or proposition that is seemingly contradictory yet reveals an essential truth through that contradiction. In this text, a paradox comes at the very end, after Mr. Bass has died and revealed that he and Falconer were the same person all along. Note what Widge remarks about this surprise and how Mr. Armin responds:
"But how could 'a bear to play a part for so long a time, and never reveal his true self?"
"Perhaps," Mr. Armin said, "it was his true self."
This is a contradictory statement because, on the surface of things, Mr. Bass created Falconer as a disguise so he could carry out his business and achieve his goals. It was not his real identity, but a figment of his imagination. This is why Mr. Armin's response initially appears to be contradictory. However, through this paradox, a deeper truth is revealed: Falconer allowed Simon Bass to express who he really was and the kind of character that he felt himself to be, that the character of Simon Bass did not allow. Thus this paradox is used to reveal an essential truth about Simon Bass and identity as a whole.