Utilitarianism is a principle where it's criteria for virtue lies in actions that maximise the greatest happiness for the greatest number of people. Bentham thinks that social problems can be remedied if we act according to this principle.For example, free universal healthcare is of benefit to everyone and conforms to the utilitarian theory that it is providing great happiness for as many people as possible. Whereas choosing to steal from everyone yields very little happiness for everyone and great happiness for the thief only.

This idea falls into the ancient theory of Epicureanism that says our actions should aim to maximise pleasure whilst reducing pain. Yet Bentham is emphasising that it's not just about pleasure but attaining justice.

Bentham's theory is founded from the most basic of human needs which is to seek pleasure and avoid pain and becomes the criteria for acting virtuously.

In Ancient Greece, Protagoras held the view that “Man is the measure of all things”; he is taking the relativist view that any claim to knowledge or any judgement in the world is relative to our point of view. He is saying that all the moral values we have and truths are ultimately subjective, we depend on ourselves to come up with definitions as there is no such thing as absolute moral ideals or objective knowledge.

For example, Is it acceptable to slaughter cows? The butcher and those that work with leather would say yes, Those that practice Hinduism or advocate animal rights would say no. Who is correct here? The relativist would say they all are, in accordance with their established beliefs. There is no universal law in nature that says we should act a certain way.

Phenomenology is a field of philosophy that tries to describe what our experience of the world is, from our perspective. It comes up with theories on how our consciousness interacts with the world. By understanding our relationship with the world, we can get closer to understanding things like our existence, what knowledge is, what ethics we should live by and so on.

So to answer questions about knowledge and ethics, some phenomenologists believe that we need to understand our existence first, some believe that we need to understand consciousness itself and some believe that we must acknowledge our freedom before we begin to understand anything else.

Levinas believes that these starting points are incorrect, because they are self-centered; looking to the self is an insufficient starting point in trying to understand how we interact with the world. What he instead suggests is looking at our relationship with others, as a starting point for developing any branch of philosophy. It’s the ethical responsibility towards the other that is the first philosophy to adopt.

So why this ethical responsibility?

When we encounter the other person, it is the most fundamental experience. There’s something that stirs deep inside when we look at the face of another, an ethical demand to be responsible, to not harm that person. This feeling is inherent, it’s automatic, it comes before any philosophical theory.

Before we come up with any theory of knowledge, the relationship between humans comes first.