‘Humanist’: A humanist is a non-religious person who believes that this is the one life we have, that we can live meaningful and fulfilling lives in the here and now, and that we should support other people to do the same. They believe science provides the best way of understanding the world around us and see no persuasive evidence to believe in a god, a higher power, or any supernatural aspects to reality. They make their ethical decisions based on empathy and a concern for the wellbeing of humans and other sentient animals, and try to make a positive contribution towards building a better society.
‘Atheist’: The word ‘atheist’ is used to describe somebody who does not believe in a god. Such an absence of belief is not a position of faith, but is typically based on their seeing no good or persuasive evidence or reason to believe in a god or gods. Knowing somebody is an atheist, however, does not tell you more about their wider beliefs, values, or worldview. Many atheists will have a humanist approach to life, but some will not. Some people who consider themselves to have a religious identity (e.g. Jewish or Anglican), perhaps for family or cultural reasons, are also atheists because they do not believe in a god.
‘Agnostic’: The word ‘agnostic’ is sometimes used to describe somebody who cannot decide whether they believe in a god or not. They are perhaps ‘sitting on the fence’. However, the original use of the word was to describe somebody who believes we cannot know for certain whether a god exists or not, and that is the sense in which many non-religious people use it today.
Some people describe themselves as both agnostic and atheist. They accept that we cannot know for certain whether a god exists or not (it’s impossible to prove that something does not exist), but they do not believe in one and live their lives accordingly.
‘Secularist’: The word ‘secularism’ was historically used to describe a non-religious worldview, and non-religious people and worldviews are still sometimes described as ‘secular’. However, the word today is normally used to describe a political position on how society and the state should be organised. Someone who supports secularism is a ‘secularist’. Humanists will typically be secularists, but so will many religious people.
‘Non-believer / unbeliever’: These terms are often used to describe somebody who does not believe in a god. Many atheists prefer not to use these words because people who do not believe in a god do, of course, hold many other beliefs (about the nature of reality, about how we should live, and about how we should treat other people).
‘Non-religious’: This term might be used by a wide variety of people who do not identify as being religious. It does not tell you much about a person’s wider worldview. Some non-religious people may hold beliefs associated with being religious (e.g. believing in a god), but most will not.
‘Freethinker’ was a term, popular in the nineteenth century, used by those who rejected authority in matters of belief, especially political and religious beliefs. It is still used in different languages in some European countries by non-religious organisations to describe themselves.
‘Rationalist’ can mean someone who prioritises the use of reason and considers reason crucial in investigating and understanding the world. Rationalists often reject religion on the grounds that they believe it cannot be founded on reason. (Rationalism is sometimes contrasted with fideism – positions which rely on or advocate ‘faith’ to some degree).
‘Sceptic’ today usually means someone who doubts the truth of religious and other supernatural or ‘paranormal’ beliefs. (‘Sceptic’ also has a special philosophical meaning: someone who rejects or is sceptical with regard to all claims to knowledge).
It is important to recognise that people will use labels in different ways, and knowing what label someone applies to themselves doesn’t always tell you a great deal about their approach to life. Once you know how somebody identifies themselves, rather than making assumptions about their wider worldview, it is better to ask them further questions about their beliefs and values.