G. E. Moore and ethics

Photo source: Wikimedia Commons, Ray Strachey

G. E. Moore (1873-1958) was an English philosopher best known for his contributions to analytic philosophy, ethics and common sense realism. Wikipedia says,

"One of the most important parts of Moore's philosophical development was his break from the idealism that dominated British philosophy (as represented in the works of his former teachers F. H. Bradley and John McTaggart), and his defense of what he regarded as a 'common sense' form of realism." (Wikipedia: G. E. Moore, 7.26.21 UTC 12:31)

The rest of this post is some quotes from Moore.

External reality

"I can prove now, for instance, that two human hands exist. How? By holding up my two hands, and saying, as I make a certain gesture,with the right hand, 'Here is one hand' and adding, as I make a certain gesture with the left, 'and here is the other'. And if, by doing this, I have proved ipso facto the existence of external things..." (Proof of an External World, 1939)

Ethics

"Moral conduct, or duty, is defined as the obligation to select that action which will achieve more good than any alternative action..." (Goodreads.com)

"For it is the business of Ethics, I must insist, not only to obtain true results, but also to find valid reasons for them." (Principia Ethica, 1903)

What is good?

"If I am asked, 'What is good?' my answer is that good is good, and that is the end of the matter. Or if I am asked 'How is that to be defined?' my answer is that it cannot be defined, and that is all I have to say about it." (Principia Ethica, 1903)

"...if 'good' is defined as something else, it is then impossible either to prove that any other definition is wrong or even to deny such definition." (Principia Ethica, 1903)

"If indeed good were a feeling... then it would exist in time. But that is why to call it so is to commit the naturalistic fallacy. It will always remain pertinent to ask, whether the feeling itself is good; and if so, then good cannot itself be  identical with any feeling." (Principia Ethica, 1903)

"We must not, therefore, be frightened by the assertion that a thing is natural into the admission that it is good; good does not, by definition, mean anything that is natural; and therefore always an open question whether anything that is natural is good." (Principia Ethica, 1903)