I was on the sidewalk in a college town with a group of friends, passing out tracts, talking to people about Jesus and giving away free sodas. A student had just said, “I just don’t think Christianity is true. What proof is there?”
“Well there’s the Bible, of course,” I replied, “But one of the most powerful testimonies to the truth of Christianity is that early Christians were willing to die horrible deaths and undergo torture for their beliefs. Why would they be willing to do that if their beliefs were not true?”
I used that argument quite a bit. It seemed airtight. Who would submit to a horrible death for something that wasn’t true?
But it’s a bad argument, as Robert Green Ingersoll shows:
All the martyrs in the history of the world are not sufficient to establish the correctness of an opinion. Martyrdom, as a rule, establishes the sincerity of the martyr — never the correctness of his thought. Things are true or false in themselves. Truth cannot be affected by opinions; it cannot be changed, established, or affected by martyrdom. An error cannot be believed sincerely enough to make it a truth. (source)
The willingness of someone to die for a belief is not proof of its truth. For example, terrorists who blow themselves up or die in battle do not establish the truth of their beliefs. And believers of all religions have been martyred: Stephen and Paul for Christianity; Sumayyah bint Khabbab and Husayn ibn Ali for Islam; Guru Arjan Dev Ji for Sikhism; Siyyid`Alí Muḥammad for Bahá’í; the list could go on endlessly.
Does this make all religions true? Of course not. It shows that all martyrs are devoted enough to their religion to die for it.
So it is a useless argument. It can be used as evidence for all religions, and thus it supports none of them.