|Portrait of John Locke|
In his letter to Locke (Dated: 27 August 1692), William Molyneux requests Locke to produce a treatise of morals. Here’s an excerpt from Molyneux’s letter:
One Thing I must needs insist on to you, which is, that you would think of Obleidging the World, with a Treatise of Morals, drawn up according to the Hints you frequently give in Your Essay, Of their Being Demonstrable according to the Mathematical Method. This is Most Certainly True. But then the task must be undertaken only by so Clear and Distinct a Thinker as you are. This were an Attempt worthy you Consideration. And there is Nothing I should More ardently wish for, than to see it. And therefore, Good Sir, Let me Beg of you to turn your thoughts this way. and if so Young a Freinship as mine have any force; Let me prevail on you.In his reply to Molyneux (Dated: 20 September 1692), Locke says:
Though by the view I had of moral ideas, whilst I was considering that subject, I thought I saw that morality might be demonstratively made out, yet whether I am able so to make it out is another question. Every one could not have demonstrated what Mr. Newton’s book hath shewn to be demonstrable: but to shew my readiness to obey your commands, I shall not decline the first leisure I can get to employ some thoughts that way; unless I find what I have said in my Essay shall have stir’d up some abler man to prevent me, and effectually to that service to the world.But Locke was unable to produce scientific laws of morality. His failure to achieve what he said could be achieved, and his appeal to theology for explaining the duty and the motivation to act morally, is a fundamental flaw in his moral theory.