Can ethics be a science? The traditional answer is, Yes, but not only that – ethics is a science.
That is what you find in Aristotle, that is what you find in Kant, Adam Smith, Adam Ferguson, James Beattie, Jeremy Bentham and so on. (Kant, for instance, agreed with the ancient Greeks that there are three sciences: logic, physics, ethics.)
This is not the standard answer nowadays. The explanation is that we have another concept of science than Plato, Aristotle and Kant had.
The traditional view was that a science is a set of necessary truths which fulfil two demands: they treat of unchangeable objects and their properties, and they can be derived from principles which are so evident that they don’t need any proof. In this perspective, Euclid’s geometry is an ideal science.
From the beginning of the nineteenth century, a new concept of science has established itself: science as methodical empirical research. And since empirical research deals with how it is and ethics with how it ought to be, one can hardly claim now that ethics is (or can be) a science.
But the traditional view has not disappeared completely. In the field of ethics, it is still alive under the name of Ethical Theory. It seems to be a widespread idea that ethics stands in need of theories.
Here is a quotation from R. B. Brandt’s textbook Ethical Theory (first published in 1959):
Ideally a normative ‘theory’ consists of a set of general principles analoguous to the axioms of a geometric system. That is, ideally it comprises a set of correct or valid general principles, as brief and simple as possible compatibly with completeness in the sense that these principles, when conjoined with true nonethical statements, would logically imply every ethical statement that is correct or valid. Such an ideal for a system must be our guide.
This is, in fact, an admirably clear way of summing up the classical conception of science.
When ethical theorizing is emphasized in this way, there is something which one tends to neglect – the crucial role of examples in ethics. General principles of human dignity, for instance, must be anchored in concrete cases in order to get substantial content. Ethical reasoning is normally not deductive; it is reasoning by analogy. This is where the core of ethics is to be found.
Or – ?