Need for a standard of action…
As beings capable of self-determined actions, every instance of our conscious existence needs a choice of action — the choice could as well be of inaction (we shall later show that we are indeed self-determined (not “purely” but fundamentally), but it is a self-evident fact). How we must act depends on why we must act, i.e. the choice to act depends on the reason to act. The reason to act depends on the nature of our existence and the potential it holds. The knowledge of the nature of our existence and its potential is what gives rise to the standard of action, i.e. the basis for effective choice. I shall show later how the standard of action is the standard of value.
Ethics and its purpose…
Ethics is the study of the code of values and principles by which we guide our lives in general and our actions in particular. The purpose of ethics is the same as for any system of abstract principles; reality is the standard of truth, but while only particulars exist as concretes, abstractions are the only means to integrate particulars in a broader context and grasp the nature of particulars beyond what we perceive so as to be effective in thought and action across (1) a vast (often unlimited) range of particulars and (2) a vast (often unlimited) span of time.
Link between epistemology and ethics…
Epistemology gives us the means to seek knowledge. Ethics gives us the means to guide our actions on the basis of knowledge. The link between these sciences is the knowledge of the nature of human (i.e. volitional) consciousness (discussed here: Human Consciousness and Free Will from Philosophy), enabling us to learn the kinds of actions that are right and most effective with respect to our fundamental nature.
Fundamentals…
Expansion…