The Art of Public Speaking Again, it is hurtful to force the memory in hours of physical weakness or mental weariness. Health is the basis of the best mental action and the operation of memory is no exception. Finally, do not become a slave to a system. Knowledge of a few simple facts of mind and memory will set you to work at the right end of the operation. Use these principles, whether included in a system or not, but do not bind yourself to a method that tends to lay more stress on the way to remember than on.