Secularists base their ethics on scientific evidence and reason. They ask, Can we have morals without a god? We explore the possibility of a system of ethics based on scientific principles and philosophical reasoning. The foundations claimed by religions are examined and found wanting. Instead, evidence from neuroscience has illuminated the nature of sentience and consciousness in humans and animals, including its limitations in space and time, and its total dependence on life for support. This leads to our core moral paradigm “respect for sentient beings”. The utilitarian principle is used to make qualitative and quantitative comparisons of the consequences of possible courses of action. The analysis is flowed down to provide enlightened policies on personal freedoms, abortion, euthanasia, justice, education and the environment.