A 16-page paper argued 'you ought to' is meaningless once the lawgiver is gone

In 1958, Elizabeth Anscombe argued that modern secular ethics kept using words like 'moral obligation' as if a divine lawgiver still stood behind them, even after abandoning the belief in one — leaving the term hollow. She urged philosophers to drop the debate over rules and consequences and return to Aristotle's older question: what does a person need to actually flourish?

— G. E. M. Anscombe, Modern Moral Philosophy — Philosophy, Vol. 33, No. 124 (January 1958)