The mind is no different than a vessel within the Bosphorus.
When we are young our minds are similar to that of a speed boat, it is agile and it easily maneuvers itself to different directions as it wishes. But as we age our frames of the world turn more into massive tankers of slow speed, which possess in it the heavy weights of experience and engraved belief systems acquired through many decades. In order to change its direction a tanker needs a long time and a good distance, which the Bosphorus does not provide due to its narrow and meandering nature.
If the tanker is heading to the Dardanelles from the Black Sea, it is virtually impossible to make a 180 degree turn within the Bosphorus. Hence no matter what pragmatic factual sound arguments we offer to a man of age, if it conflicts with his long standing beliefs he will never accept it. Where a speed boat could easily entertain new ideas with or without fully accepting it.