Abstract: Aspects herein describe new methods of determining optimal actions to achieve high-level goals with minimum total future cost. At least one high-level goal is inputted into a user device along with various observational data about the world, and a computational unit determines, through particle methods, an optimal course of action as well as emotions. The particle method comprises alternating backward and forward sweeps and tests for convergence to determine said optimal course of action. In one embodiment a user inputs a high-level goal into a cell phone which senses observational data. The cell phone communicates with a server that provides instructions. The server determines an optimal course of action via the particle method, and the cell phone then displays the instructions and emotions to the user.