Without realizing that the past is constantly determining their present actions, they avoid learning anything about their history. They continue to live in their repressed childhood situation, ignoring the fact that is no longer exists, continuing to fear and avoid dangers that, although once real, have not been real for a long time.
He knew perfectly well (even if he wasn’t inclined to admit it) that the material body had a spiritual aspect. He knew that “spirit,” however explained, was real, because of his own undeniable experiences - which, though he might suppress them, he couldn’t altogether erase from memory.
The human mind isn't a terribly logical or consistent place. Most people, given the choice to face a hideous or terrifying truth or to conveniently avoid it, choose the convenience and peace of normality. That doesn't make them strong or weak people, or good or bad people. It just makes them people.