Aristotle once described humans as “the rational animal.”
what Aristotle meant is that rationality is our distinguishing characteristic – it’s what sets us apart from the beasts.
when Plato was laying out how reason can, and should, function in the human mind. He believed that we all have what he called a tripartite soul – what you might think of as your “self,” or your psyche, divided into three parts.
there’s the rational, or logical part of the soul, which represents cool reason. This is the aspect of your self that seeks the truth and is swayed by facts and arguments.
there’s the spirited aspect, often described as the emotional part of the self, although that doesn’t really quite capture it. The spirited soul isn’t just about feeling -- it’s also about how your feelings fuel your actions.
The appetitive part is what drives you to eat, have sex, and protect yourself from danger. It is swayed by temptations that are carnal, and visceral.
Plato believed that the best human beings -- and I should point out here that Plato most definitely did believe that some people were better than others -- are always ruled by the rational part of their soul
here’s a doozy, from 20th century British thinker Bertrand Russell, one of the pioneers of what’s known as analytic philosophy. Say there’s a town in which all men are required by law to be clean-shaven. This town has only one barber, a man, who must follow strict rules: Rule number one: He must shave all men who do not shave themselves. Rule number two: He must not shave any man who does shave himself. It’s the nightmare of every libertarian and every mustachio’d hipster. But here’s the question: Does the barber shave himself?
Russell came up with this puzzle to illustrate the fact that a group must always be a member of itself.
if the barber is a logical impossibility, then he can’t exist, which means the reasoning behind his existence is inherently flawed.
An argument, in philosophy, isn’t just a shouting match. Instead, philosophers maintain that your beliefs should always be backed up by reasons, which we call premises. Premises form the structure of your argument.
There are actually several different species of arguments. Probably the most familiar, and the easiest to carry out, is the deductive argument.
The main rule of a deductive arguments is: if your premises are true, then your conclusion must be true.
Validity is not the same as truth. All ‘valid’ really means is that if the premises are true, then your conclusion can’t be false. But that doesn’t mean that your premises prove your conclusion to be correct.
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