My only fear is the unknown.

Taken at face value, the line frames fear not as a reaction to pain, danger, or failure, but as a response to uncertainty itself. In the context of an endurance performer like David Blaine, it suggests that preparation can blunt many anxieties—training, planning, and experience make known risks feel manageable—while what remains unsettling is what cannot be fully anticipated: hidden variables, unforeseen bodily limits, or uncontrollable conditions. The statement also implies a disciplined mindset: fear is narrowed to a single category, which can be studied and confronted. As a credo, it elevates the “unknown” into both the adversary and the attraction that drives extreme feats.