We can never know the actual reasons why we do anything. The observations of split-brain patients reveal that our true motivations are unknown behind all logical decisions.
Split-brain patients, whose left and right brain hemispheres cannot communicate, have uncovered a mind-boggling secret about decision-making from a neuroscience perspective.
Researchers have conducted experiments with split-brain patients. They instruct the patients in their right ear: "Please open the window," and they will open it. The brain connected to the left ear has no information about the instruction given by the researcher. However, when asked in the left ear why they opened the window, the patient replied confidently, "I opened it because it's a bit cold here." And they genuinely believe that's the reason they opened the window.
A couple of similar instances exist where one side of the brain acts upon information unknown to the other. And the patient will always make up a reason why they do that. The patients don't know they are making it up and feel completely confident that the made-up reason is why they did it.
This phenomenon is not limited to split-brain patients and is often true for us. We interpret our behavior in a way that makes it seem like a logical decision when our true motivations are unknown. We can never know the actual reasons why we do anything. Therefore, we shouldn't even believe anything we tell ourselves.