I don't like defining myself by a selection of tickboxes on a form and get annoyed when forms ask me to tick a religious category as I rarely agree with the categories. It is apparent that although it is easy to categorise people by their faith when they have one, everyone else gets lumped together. Terms such as humanist and secularist also get misunderstood.
Firstly we have those who belong to a religion. They are always happy to tick the box that says Christian, Muslim, Bahai, Jain... There might be different subdivisions of these faiths and difference in beliefs but these people know where they belong even if they don't necessarily agree with all the tenets of their faith. And, let's face it, many who tick that they belong to a religion never actually go to their place of worship and participate but nevertheless consider themselves a member, leading to phrases like "cultural Christian" coming into use.You can include adherents of the Flying Spaghetti Monster within the religious belief category. You may consider it to be a pretend religion, but what's a real religion and how are they different?
Secularists believe, quite simply, in the separation of church and state. This means that any faith group should not hold a position in the state or have their views counted more than anyone else's. In Britain secularists campaign for removing bishops from the House of Lords and for the abolition of faith schools. There are many other campaigns that are run by the National Secular Society, Britain's largest secular society. The NSS has recently decided not to allow faith members in on the basis that although there are many believers who think that faith should stay out of government it should stay a non-faith movement. The Accord Coalition is a truly secular group of people and organisations that includes faiths and non-faiths who are campaigning, amongst other things, that admissions to faith schools should not be based on religious belief, believing that such discrimination is divisive and does nothing for community cohesion.
Humanists are more difficult to define in a clear cut manner. There are many different definitions. Essentially humanism is about a belief in collective responsibility and connection with other humans. For me that means we have a duty to consider how our behaviour affects people on the other side of the world, people whom we will never meet or know but who we can affect indirectly. It's about recognising our common humanity as well as our connection with future generations. Many people of faith could if they choose define themselves as humanists as it doesn't necessarily conflict with their beliefs. The British Humanist Association is the largest group of humanists in Britain and they define 3 main tenets of humanism to be trust in the scientific method rather than the supernatural (thus rejecting faith), we create our own ethical system based on reason and empathy and that we give our own lives meaning.
So these two groups include people with or without faith, depending on how you define them.
Article 9 of The Human Rights Act protects people's "religion or beliefs" and various court cases have determined that humanist views form a belief system which should be considered equal alongside religious faiths.
Agnostics believe that there may be some sort of deity but they're not sure what and don't know. It can be anything from hitherto undefined deity or a universal consciousness, Both religious believers and atheists tend to rudely consider this as fence sitting.
Atheists have made a conscious decision that they do not believe in a god. Some declare that they would change their mind if faced with evidence of a god; others won't. (Others argue that if you're prepared to change your mind then you're agnostic.) Any rational scientist would be happy to change their mind if the evidence suggested the necessity as should atheists and anyone else with a sceptical healthy enquiring mind. There is no sacred book, no deity or set of beliefs that you must sign up to in order to be counted and that freedom is one of the joys of not believing.
Atheists are, by definition, defined by what they don't believe in. It's very difficult to define yourself by a negative (one of the only other groups I could think of is those against a third runway at Heathrow). How then to redefine this as a positive? One of the few places I can put a user-defined entry for religious views is Facebook. I thought about putting sceptic by which I mean someone who questions facts and authorities and who tries to look at the evidence rather than someone else's interpretation. I regard that as a state of mind rather than a belief so I settled on freethinker, a word that has fallen out of vogue but means that I am free to think for myself, that I have no creed that I must follow; I will try and think rationally to further my understanding rather than follow someone else's beliefs.
Then there are those who have never really thought about it and/or who really don't care. Should they be included with the atheists? Some would argue that people are born atheist and have religion or doubt taught to them, that we are all atheists by default. There are of course many people who class themselves as believers who have simply never really thought about it. I think I'd like to see an “Uncommitted” category for these, to include both believers and non-believers.
So what am I? I am above all a person, a human who doesn't like tick box categories. If I have to choose then I am an atheist who is a secularist and a humanist. I define myself differently according to the company I'm with as they all mean slightly different things and if I call myself a freethinker I get looks of incomprehension. Hence the confusion with those who find it easy to tick boxes.
What do I believe in? I think that we have to find our own way through the ethical quandaries that will face us in life, by thinking things through for ourselves and making decisions based on the evidence, constantly questioning facts and searching for the truth. I also firmly believe that I must be prepared to change my mind if I'm wrong. I strongly believe in the value of separation of church and state including the abolition of faith schools. I had no sacred books to follow; those authors who I read extensively as a teenager who helped form the way I think include Upton Sinclair, Isaac Asimov and Robert A. Heinlein.