Medieval missionaries found it easier to attack Islam than to prove Christianity’s truth

Evidence

Rather, first and principally one must insist on showing how vain their law is. For one cannot inculcate virtues before extirpating vice. And this method should be chosen since it is simpler; for it is easier to show that their faith is frivolous than to prove that our faith is true, because faith is an invisible gift from God. Whereas our faith has existence without appearance, theirs has appearance without existence. We do not have arguments [rationes] for proving the Trinity and the other things of our faith, for if we did faith would not be faith, and it would not be merito- rious. — John V. Tolan, Saracens, 1261

Categorization

• XREF: The ‘faith without arguments, else it wouldn’t be faith’ logic anticipates modern fideism debates — connects to my interest in the epistemology of religious belief.
• DEEPTHINKING: The asymmetry between positive and negative apologetics — attacking the other’s religion is structurally easier than defending one’s own because faith by definition resists proof — is a genuinely dense epistemic point about the logic of religious polemic.