A friend recently asked me about apostasy in relation to the film Silence. Here's an interesting analysis of the novel on which the film is based:
In response to my friend's inquiry, I said the following:
i) "Apostasy" is a term of art. It didn't fall from the sky. And it can be used to cover a variety of different phenomena.
ii) We can draw a rough-cut distinction between doxastic apostasy and behavioral apostasy. Up to a point, psychological apostasy involves loss of faith. A professing Christian ceases to believe the essentials of the faith.
iii) That would be a necessary, rather than sufficient condition inasmuch as that can be a temporary condition. It goes to a distinction in Reformed theology between apostates and backsliders, where a backslider may suffer a temporary loss of faith.
iv) Apropos (iii), there is also the distinction between the emotional problem of suffering and the intellectual problem of suffering. A professing believer may suffer a crisis of faith due to personal tragedy. It's not so much loss of belief, but loss of trust. Anger. Disillusionment. He may not have reassessed his views regarding the evidence for Christianity. Rather, he no longer cares whether or not God exists, because God let him down.
v) You also have people with a default faith because they grew up in a religious community. They shed that when they find themselves in a different community. There was never much conviction to it. They are social chameleons. Their stated beliefs blend into the social background of whatever peer group you put them in.
vi) On a behavior definition, apostasy is the public recantation of the Christian faith. The individual doesn't quietly lose his faith and keep it to himself, or privately share his loss of faith when questioned. Rather, it's more like a conversion experience where he replaces Christian faith by adopting something else: usually militant atheism.
vii) Or someone might openly renounce the faith out of fear. And sometimes behavior mirrors lack of conviction and commitment. They were never that attached to Christianity. It's circumstances that forced the issue.
viii) In that respect, some of them are freeze-dried apostates: just add water.
By that I mean, depending on the situation, they might be lifelong professing believers, because it was never put to the test. Or they never had occasion to question their faith. They lived and died in homogenous communities where their nominal faith was constantly reinforced. Yet they were apostates just waiting to happen.
ix) However, if we consider the doxastic makeup to be a necessary condition, then that's an insufficient condition. Repudiating the faith under duress doesn't necessary mean any change in what you believe. Conviction and conformity are separable in principle, and sometimes in practice.
To take a comparison, consider people living under communism who go through the motions to survive. They say whatever's needed to keep up appearances, but they don't take communist ideology seriously, and they will drop the pose the moment they are free to do so without fear of reprisal.
x) Or suppose you have an Arab Christian whose recruited by the military or law enforcement to infiltrate a jihadist network. He can pass for a Muslim. He speaks fluent Arabic. He's conversant with Muslim culture.
As an infiltrator, he must pretend to be a Muslim. Recite Muslim prayers.
Suppose, as a rite of initiation, leaders of the jihadist network require him to urinate on a Bible or an icon of Jesus. That's sacrilegious, but he does so to maintain his cover.
xi) One final point: it wouldn't surprise me if many people in the past had a somewhat higher pain tolerance than moderns do. Life was physically more painful back then. No anesthetic.
Likewise, there were many painful, but untreatable and incurable diseases. If you got one, you had to live with it. No symptom relief. Moreover, it could be cumulative, if you developed one painful condition after another.
Point being: contemporary Christians might be more likely to break under torture or even the threat of torture than their forebears.