Rather than the practical pursuit we are accustomed to, for Plato, Politics is an intellectual faculty. Governance by non-philosophers is to be governed by opinions, beliefs and self-interest; in contrast the philosopher ruler will govern with virtue and justice with no hidden agenda. The philosopher is in love, in love with learning, knowledge and truth. It is important to make a distinction here between the acquisition of knowledge and the acquisition of truth, because knowledge is not necessarily the truth.
The fundamental prerequisite to becoming a philosopher ruler is to have knowledge of the forms, therefore knowing the truth. The forms do not exist in the sensible world, they can only be found in the super-sensible world. Platos‘ theory of the forms is partly logical and partly metaphysical. The logical part is, take for example a dog, there will be many types of dog, and general particulars regarding a dog. The form of a dog is universal and eternal it has no position in space or time, it is not born when a dog is born, nor does it die when a dog dies. The metaphysical part of the theory is the form of a dog is a perfect, unique dog, created by God. The dog is real, particular dogs are apparent. Armed with this truth, the philosopher rulers will always make the right decisions, and rule with total wisdom, justice and virtue. The rulers will not own property, nor have money, they will be free of vices, excesses and desires. They will have a Spartan existence (Plato was an admirer of Spartan culture). A ruler in Platos' society as described in his dialogue The Republic would be incorruptible, an absolute model of sensible world perfection and justice. If one was to look no further into Platos‘ utopian society you could be forgiven for thinking that the philosopher rulers would be the ultimate answer for political duties and government administration. A more detailed examination of policy and structure is necessary, prior to arriving at a conclusion.