The very fact of memorizing is wrong. Understanding is the key. When we memorize we just try to mechanically validate a point which we haven’t experienced yet. This false knowledge could result in failure or even worse, dangerous results as we won’t have the capacity to change when it is needed. We just use the memorised knowledge to a problem and not genuinely understand to solve it. But if we understand how it works then we would hardly have to memorize and we also will have the capacity to change and apply to suitable problems to solve them.