So you can have a mind that rejects modus ponens but does this matter? Is such a mind good for anything?
The “argument” that compels me about modus ponens and simple arithmetic is that they work with small real examples. You can implement super simple symbolic logic using pebbles and cups. You can prove modus ponens by truth tables, which could be implemented with pebbles and cups. So if arithmetic and simpler rules of logic map so clearly on to the real world, then these “truths” have an existence which is outside my own mind. The only human minds that could reject them would be bloody-minded and alien minds which truly reject them would be irrational.
Can you have a functioning mind which rejects lying is wrong or murder is wrong? People do it all the time and appear to function quite well. Moral truths don’t have anything like the compelling-ness (compulsion?) of arithmetic and logic. My own intuition is that the only sense in which morality is objective is the sense in which it is descriptive, and what you are describing is not a state of what people do, but what they say. Most people say lying is wrong. This does not stop us from observing the overwhelming prevalence of lying in human society and human stories. Most people say murder is wrong. This does not stop us from observing that murder is rampant in time and space.
And there is a prescriptive-descriptive divide. If I accept that “murder is wrong” is an objective “truth” because most people say it, does this compel me to not murder? Not even close. I suppose it compels me to agree that i am doing “wrong” when I murder. Does that compel me to feel guilty or change my ways or accept my punishment? Hardly. If there is an objective-ness to morality it is a way more wimpy objectiveness than the objectiveness of modus ponens and arithmetic, which successfully compel an empty bucket to which have been added 2 then 3 apples to contain 5 apples.
So you can have a mind that rejects modus ponens but does this matter? Is such a mind good for anything?
The “argument” that compels me about modus ponens and simple arithmetic is that they work with small real examples. You can implement super simple symbolic logic using pebbles and cups. You can prove modus ponens by truth tables, which could be implemented with pebbles and cups. So if arithmetic and simpler rules of logic map so clearly on to the real world, then these “truths” have an existence which is outside my own mind. The only human minds that could reject them would be bloody-minded and alien minds which truly reject them would be irrational.
Can you have a functioning mind which rejects lying is wrong or murder is wrong? People do it all the time and appear to function quite well. Moral truths don’t have anything like the compelling-ness (compulsion?) of arithmetic and logic. My own intuition is that the only sense in which morality is objective is the sense in which it is descriptive, and what you are describing is not a state of what people do, but what they say. Most people say lying is wrong. This does not stop us from observing the overwhelming prevalence of lying in human society and human stories. Most people say murder is wrong. This does not stop us from observing that murder is rampant in time and space.
And there is a prescriptive-descriptive divide. If I accept that “murder is wrong” is an objective “truth” because most people say it, does this compel me to not murder? Not even close. I suppose it compels me to agree that i am doing “wrong” when I murder. Does that compel me to feel guilty or change my ways or accept my punishment? Hardly. If there is an objective-ness to morality it is a way more wimpy objectiveness than the objectiveness of modus ponens and arithmetic, which successfully compel an empty bucket to which have been added 2 then 3 apples to contain 5 apples.