Firstly, there is a vast difference between Christian and secular, humanist ethics, although far too few people recognize the size of the gap between them. While Christians and humanists both agree that murder, rape and theft, etc are wrong, the two sides are marching to different drummers and their ways of life differ.
The fundamental questions of ethics are:
- how should I live in society
- what sort of respect do I owe other beings
- of what does human excellence consist
- and linked to this last question, what sort of character should I have
Secular ethics as practised by humanists is an ethical system that is centred on enlightened self-interest. It regards humans as rational beings who want to assert their own rights, but who need to live in a society where others have rights as well, and it believes that it is in our mutual interest to respect the rights of others. Beings other than humans are often, though not always respected, and given their due weight in ethical decision making. Utilitarianism, a form of secular ethics, asserted from early on in its history that animals have to be considered as well as humans, though utilitarianism disbelieves in rights. There is no goal to secular ethics other than a shared acceptance that humans are here but once and that they want their lives to be as comfortable as possible, and humanists recognize that this involves ensuring that others have the same consideration as they do. In humanist ethics there is no room for gods or higher spiritual beings, who are not believed to exist. Love is praised, but not required,and self-sacrificial love may be admired, but it is not even an ideal.
Here we find one point of contact between Christian and secular ethics: the principle of giving due regards to all beings. It is clear that humanists/secularists have a reasonably good record on animal rights, because they recognize that animals merit due consideration, not as much as persons in most cases, but certainly consideration for their need to live and die without pain and in some dignity. Christians might agree, but they point out that there is a higher being who is greater in power, wiser and far better than humans are, and this being deserves proportionally great respect, service and love. Thus they regard this being as their leader, the source of their law. Christians obey God, not as mere slaves to a tyrant in the sky, a capricious old man with a beard, but a loving leader whose wisdom extends far beyond the wisdom of humans, and who can therefore guide us in the right path.
Another point of contact between Christians and humanists is that both believe that life matters. But while the humanist believes that there is but one life that should be enjoyed to the full for the brief time that it exists, while Christians set this life in the context of something longer, even infinite, that extends beyond death. This next stage of life matters. But the humanist accusation that Christians focus exclusively on the next life might be true for some Christians , but in most cases Christians work for a better world and believe that this life really matters, which is why they do so many acts of charity.
This takes us to a key point of Christian ethics: it is teleological, which means that it is goal directed. The goal is to have life eternal, and so Christian ethics aims not only at happiness in this life, but happiness beyond life. Secular ethics does not.