In "An Enquiry Concerning Human Understanding," David Hume makes the case that nothing is really ever known, per say. The familiarity with Cause and Effect of situations is about the extent of what is ever "known" about anything. He makes a great case for the applicability of this idea.
However, I found myself wondering about the disorder I have struggled with my entire life. Obsessive Compulsive Disorder. Cause and effect are considered, but the cause, the effect, or both are often irrational in the mind of one with OCD. It is not due to a lack of understanding, either. In my own experience, these individuals, myself included, become quite obsessed with logic and reasoning, perhaps because of the insufficiency naturally afforded to us.
Rational Cause - Rational Effect - Rational Correlation Brick thrown at window - Window shatters - Heavy object with momentum will break glass. The process can be repeated and tested, and will prove itself a reasonable assumption for the outcome. Now, let's go down some of the examples of the irrational that are not as uncommon as they should be. Watch TV, something catches attention - Later, something very similar happens in real life - That was a warning sign, I could have avoided this. They're connected. Next time something odd catches your attention, you have an increased likelihood to alter your behavior through irrational fear. I saw rain on three tv shows today, therefore, I should stay home so I'm not out when a storm appears and I could get struck by lightning. It may sound like a hyperbole, but it is not very distant from real examples.
All of us have the ability to think in these erroneous ways, but it often has no meaningful consequences. It makes people a bit peculiar, but often does not disrupt their life. With OCD, the disconnect between rational cause and effect relationships actively interferes with life daily. If openly expressed, it came come across very confusing to an observer who cannot empathize. For example: I have to wash my hands because I touched the floor or _____ will die. On it's surface, it seems ridiculous and few would understand why the thought couldn't be dismissed easily.
The reason is because that isn't really the cause and effect. It's the result of a flawed chain of causes and events that have been incorrectly correlated, but feel very real to the individual experiencing them. "I have to wash my hands because I touched the floor or _____ will die." If this were said, it would not per say mean that the person believes those two things are directly connected. What is happening is a chain. Expanding that example, it would more accurately sound like: "I touched the floor, the floor has germs, germs are contaminates, contaminates harm others, if I don't wash my hands I will eventually touch something that someone else will eventually touch, thereby infecting them with the contaminant, this could lead to spiraling decline in health to the point of death and it otherwise would not have been set in motion had I washed my hands.... I better wash me hands." Rational? Not at all. It is a lot more understandable to others, though. However, if you ask someone why they are doing something repetitively, they may just answer with the end fear that they are trying to alleviate by submitting to the compulsion.
Rational thinking will remind you that not only is that unlikely, but it is likely true that you could not do that intentionally if you were really trying to. So it's resolved? No, the brain has a retort. "What if?"