Which means that, in order to be converted, reason is not enough. IOW in order to convert, apprehending something is not enough.
Apprehending something means that reason is necessary, but it might not be sufficient. Reason ”presents the truth" to our imagination, our world view, but it takes an act of will to accept it or “grasp” it as the dictionary definition entails. This grasping step depends upon one’s world view, open mindedness, commitment to a certain mindset, among other things that could cause someone to deny a truth presented by reason.
I suggest that apprehending is a two step process (at least) but done very quickly by the mind so it seems to blend into one. The steps are: 1) arriving at a truth presented by rational or logical clarity; 2) acceptance or rejection of that truth by an act of will based upon a “disruptive” factor, i.e., its impact on other deeply held beliefs that are part of one’s world view.
A macro example might be the truth of global warming. Let’s assume (I understand this is debatable) that human activity is causing a massive disruption to the environment which will have deleterious effects to all life and this has been proven beyond a shadow of a doubt. The truth of this conclusion does not mean every human is going to radically alter their lifestyle to mitigate the impact. The phenomenon is more like having to change the direction of a large ship, its done very slowly and, by some, not at all, because of the habits, character and routines of the individuals being called to change. There is a great reluctance to change and a great impetus to rationalize the status quo.
If you seriously believe truth merely requires demonstration to be accepted, watch a few commercials on TV. Clearly, appeals to intellectual vanity, ego, pleasure, sloth, social acceptance, fear, insecurities, etc. are far more effective in persuading buyers to “apprehend” or buy into product lines than truth. For, I dare say it, most people, when it comes to altering a chosen lifestyle, the denial of truth is an habitual trait, unless that truth can be jerry-rigged somehow to make it ride on top without upsetting the apple cart of one’s chosen lifestyle craftsmanship.