The modelling approach is proposed as a novel way to make progress in the discipline of Philosophy. In this arena, the special advantages of modelling, i.e., the use of unique mathematical and algorithmic specifications of technical terms, could be of crucial importance. The paper initially presents an overview of a number of important philosophical issues as a means of providing background on their significance and an explanation of the difficulties arising from present philosophical methodology. It then introduces the modelling concept as a way of developing a more consistent and defensible approach. The modelling is developed at two levels. One is a general conceptual approach based on a specified mechanistic hypothesis supported by arguments from evolution. The second is a very specific operating model of psychological behavior called "Catspaw" which has strong philosophical implications. The topics discussed and on which the models shed considerable light, include free will, ethics, and the purpose of existence. These ramify into other relevant topics such as ethical activism, responsibility for good and bad behavior, a rationale for sentencing in the criminal justice system, and our obligation to act in accord with our purpose. The validity of the models' assumptions and conclusions, though not proved in an absolute sense, is strongly supported by the way they explain and interrelate a large number of long-debated philosophical issues in a fashion consistent with evolution and the physical sciences.