Statements such as "It's (*) raining
Changing a modus ponens to a modus tollens is sometimes called this philosopher's namesake "shift," a term coined by William Rowe. Like Hastings Rashdall, this philosopher advocated an ethical system called "ideal utilitarianism," according to which pleasure is not the only quality which should be maximized. This philosopher elucidated the paradox of analysis, which states that definitions cannot both be correct and informative. Statements such as "It's (*) raining but I don't believe it's raining" illustrate his namesake paradox. This philosopher held up his right hand and said "Here is one hand" to prove the existence of an external world. He argued that the concept of "good" is indefinable in a book on ethics which argued against the "naturalistic fallacy." For 10 points, name this author of Principia Ethica.
Changing a modus ponens to a modus tollens is sometimes called this philosopher's namesake "shift," a term coined by William Rowe.
G.E. Moore [or George Edward Moore] 