Vs. me mory: we make things meaningful in many different ways, so there are many dimensions that must be considered during remembering. Relevance realization is required to explain memory in order to explain categorization. Cognition requires intelligence, though maybe problem-solving is more basic than both memory and categorization! Content addressability: having to organize memory in order to facilitate zeroing in on the relevant information. I l l-defined: ill-defined problems are difficult to. Formulate, while well-defined problems are easy to understand but it may be difficult to take the necessary steps to solve the problem. I nitial state: in which there is an unsolved problem, a desired goal whose method of attainment is not yet apparent. Operators: actions one may do to alter the initial state in the hopes of approaching the goal state. Path constraints: must be obeyed during problem-solving attempts, whether or not they are related to or essential for achieving the goal state.