In: Psychology
Logic is about conclusions which must follow from the known truths.
To defy logic one must act in a way contrary to the logic. This means that if one knows that X causes Y, one does X expecting Z instead of Y. For example, If you know that drinking and driving is dangerous and you drink-drive believing you are safe, you are defying logic.
Love is depicted as a cognitive and social phenomenon in psychology. Love sometimes defies logic as the person in love starts listening to heart rather than the mind or brain. Most decisions human beings make and their thoughts and actions result from previous unconscious causes. Perhaps all in fact as free will could be a mere illusion and not a real possibility within the flow of chain and necessity. So, the decision to love and to keep loving defies logic when it breaks the causality chain through the actions of forgiveness and redemption.
This logic defying love sometimes becomes the most logical thing as it is the most logical decision an human person can take as it escapes from the tyranny of causes and consequences.Love is the result of understanding, the more you understand the more you love and the more you love the more you understand.