by Paul Braterman
What's wrong with this argument? More than you think!
All men are mortal.
Socrates is a man.
Therefore Socrates is mortal.
It's perfectly valid, meaning that if the premises are true, the conclusion must also be true. Despite this, as Bertrand Russell explained very clearly many years ago,[1] the argument is almost totally worthless.
There is no real doubt that Socrates is mortal. Just look at the poor chap, clearly showing his 70 years. Bent, scarred from the Peloponnesian War, his brow furrowed by decades of unhappy marriage, and even more unhappy attempts[2] to persuade his fellow citizens that the best form of government is a fascist oligarchy. Besides, he is on trial for doubting the existence of the gods, and the news from the Agora is not good. Take my advice, and do not offer him life insurance.
Even if we didn't know about his circumstances, we would readily agree that he is mortal. We see decrepitude and death around us all the time, few people have been known to live beyond a hundred years, none beyond 150, and we have no reason to believe that Socrates is any different. In fact, from our experience, we are a lot more certain that Socrates is mortal than we are that all men are mortal. Ganymede, Elijah, and the Virgin Mary were all, according to various traditions, taken directly up into heaven without having to go through the tedious process of dying. However, no Zeus-worshipper or biblical literalist or devout Catholic would for such reasons doubt the mortality of Socrates. So the premise, that all men are mortal, is actually less certain than the conclusion, and if we seriously doubted Socrates's mortality, we would simply deny that premise. In other words, this classic example of deductive logic tells us nothing that we didn't already know.