In simplified terms there are three ways of making ethical decisions:
The person making the judgement holds particular values, and determines what is ethical from their values. The question is, where do those values come from? For many people (not just those holding a religious faith) the values will come from a religious background, either from upbringing, or the fact that British Society has been formed from Judaeo Christian values.
I am a mathematician by training, and in mathematics you always have axioms:
axiom: a proposition that is not actually proved or demonstrated, but is considered to be self-evident and universally accepted as a starting point for deducing and inferring other truths and theorems, without any need of proof
In ethics I believe that there are also axioms – the beliefs that you hold without being able to prove them. What is beneath the last turtle!
For me, all ethics are value based, as if you choose Rules, then you have used something to make the decision to do so; if you use Consequences you need to have a means to evaluate different outcomes.
Whilst it is true that you do not need religion to arrive at values I believe that many people (including the non religious) do so; again, whilst you can arrive at “good” values (however that is judged, and we are on circular ground here) without religion you can also arrive at “bad” values. An interesting question is whether “good” values can lead to bad ethics; I think that this is possible, but don’t have time to work it through today!
There are a set of rules, like laws, which you follow. However, the question is where those rules come from. Some people will argue that the Bible, or other religious texts, give us clear laws that we should follow. However, for those without a faith, this does not seem reasonable in all cases. Also, for some with faith, particularly those for whom the Bible is not always clear, this is also a problem. For example, there are “clear Biblical rules” on lending money at interest which very few people follow; also, for many years slavery was thought to be a Biblical rule.
Here, the behaviour is judged on the outcome, rather than by a rule, but again the question is how do you judge the outcomes?
This approach can lead to Situation Ethics, where in similar, but different, circumstances different decisions can be though ethical because of the difference.
Giles Fraser tells that he used to lecture new Majors; the Armed Forces Act (2006) is so long that the chances of a soldier under fire being able to remember the appropriate sections is negligible; the chances of a soldier under fire being able to work out, let alone evaluate, the consequences of their action are also negligible; that only leaves values. He then points out how regiments have developed Regimental values over the years, and how this contributes to the ethical behaviour of the armed forces.