I have been at a festival and missed this. I'll try to add more later, but for now I'll just say:

Logic and its rules are NOT subjective inventions. They are inductive rules extracted from our awareness of our own experience. Formulations of them vary according to individual & language, but they are similar to rules of mathematics, in that they are above reference to content...... they are used to describe and manipulate content. We use math to measure, describe and understand the universe, and we use formal & informal logic to describe and understand our own processes of reasoning. No amount of logic can give us 'truth', but it can tell us if our reasoning processes have contradictions. It is 'possible' to reach *true* conclusions using bad logic, but this does not verify or justify bad logic.