The structure of any logical argument begins with a number of ‘factual’ statements, (for our purposes we’ll only be using 2 although in real life there are usually a couple of statements) which we are going to refer to as the premises of the argument as they are the statistics, facts or rules that any logical argument is built from. The conclusion of the argument is their stance on the matter, e.g. pro-life or pro-choice and the validity is whether their line of reasoning seems logical and you can clearly see where they have drawn off their original premises if you can’t follow their reasoning or it simply doesn’t match up then their argument is invalid.
The trivial part of this concept is that two people can start with the different yet equally factual and true premises and both follow a logical line of reasoning leading to a valid argument but their logic results in contrasting conclusions. For example on the topic of abortion someone who is pro-life might have the premises that murdering people is wrong and abortion is murder which would lead them to the conclusion that abortion is wrong, which is a valid argument, on the other hand, someone who is pro-choice may have the premises that murder is wrong except in self-defence and abortion is self-defence leading them to a valid conclusion of abortion not being wrong. They are both equally valid arguments yet completely contrasting which is the difficulty here, if you are faced with two equally valid arguments how do you choose one over the other? Personally, I feel that I would go with the one already supports my view of the topic which is a way of placing my own bias onto what is supposed to be a decision made solely on reason and logic. This is how legal systems and really the politics of most countries operate with the big decisions being made in this way which begs the question: how far can logic and reason take us in reality?
Thanks Saniya. You are correct that reason can led to opposite views, depending on choice of premises. And I agree with your observation – that humans tend to pick whichever premises support a desired conclusion. But that is what people DO do. Another question might be “what SHOULD people do?” After all, if reason is a path to reliable knowledge, as we had hoped, then surely we can do better than saying ‘just pick whichever argument you like’. I think perhaps there is a better way here – which is to examine the premises for two things:
(i) if they are factually correct, and if not, what that tells us. In you case you mention “murdering people is wrong” – not a bad rule of thumb, but there are exception, I think, and examining those can tell you a lot, and might lead to principles which might have a different implication for abortion.
(ii) if accepting a premise leads to silly conclusions elsewhere. We can return to this when we get to ethics
Good post; thank you. And well done for a great first term in TOK 🙂 I thought you have very good clarity and insights into the nature of logic. Thank you for your contributions in class last lesson.
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