In Section 1 (pp. 1.3:80-3) we observed that a correct theory must work in practice. In particular, a correct ethical theory must work for human beings in realitythat is, the moral and the practical are one and the same.
We often heard it said of an idea: "It's right in principle, but it just won't work in reality." Let us examine the only two possibilities:
- If the idea really cannot work in reality, then the principles on
which it is based cannot be correct: they must not have been
derived from reality by a valid, objective process. In short, the
idea is wrong even in principle.