There is a way we can give someone knowledge of a conclusion by showing that there is no difference to something else that they know has the same conclusion. This is called arguing from analogy. Here is an example:
Pretending to owe a friend less money than you actually do is wrong. Cheating on your taxes is the same thing, so cheating on your taxes is just as wrong.
This argument is unsound. It is unsound because the premise ‘cheating on your taxes is just the same as pretending to owe a friend less money’ is false. One immediate difference is one is a friend and the other is the government. These things are called disanalogies, which are things that are different between the two situations being used in the analogy.
Here is a better way to make the same argument:
Pretending to owe a friend less money than you actually do is wrong. There are no relevant differences between pretending to owe a friend less money than you do and cheating on your taxes regarding it is wrong. So, cheating on your taxes is wrong.
This is a better argument, because the premise ‘there are no relevant differences between pretending to owe a friend less money than you do and cheating on your taxes regarding it is wrong’ acknowledges that there are differences between the two, but the differences are not relevant to the conclusion being argued for. Here is a logical form of how to make arguments from analogy:
- 1. A is b
- 2. There are no relevant differences between a and c regarding them being b
- 3. C is b
This approach to arguing from analogy is always valid, because if there are no difference between a and c regarding them both being b, it would have to be the case that c is b. However, we still have to see if the premises are true. Someone could argue that there are relevant differences in the cheating on taxes and lying to your friend, that it’s ok to do this to the government but not to your friend. So the dispute will be which differences count and do not count as relevant.
In philosophy, arguments from analogy are used in many cases in the form of thought experiments. Thoughts experiments are when we use an imagined or hypothetical situation and draw conclusions and use the consequences of those situations to draw a conclusion.
Regarding argument from analogy, a famous example was made by Australian philosopher Peter Singer (1997), where he asks us to imagine seeing a child drowning in a shallow pond, and we would without hesitation save the child even if it ruined our new shoes, which would cost some money to replace. Singer says there is no relevant difference between ruining our shoes to save a drowning child and spending the same amount of money to give to charity that will definitely save at least one child’s life.
In standard form, this is Singer’s argument:
- 1. We should save a child from drowning at the expense of our shoes.
- 2. There is no relevant difference between saving a child from drowning at the expense of our shoes regarding giving to charity to save a child’s life
- 3. We should give to charity to save a child’s life.
One could argue that there is a relevant difference, and that is one of distance. However, is distance really relevant regarding the cost we are willing to occur to save a child’s life? Some philosophers believe that it is morally relevant, and others do not. The reasons will not be discussed now, but it is important to note what is in dispute when analysing thought experiments in the form of argument from analogy.
See here for Singer’s argument in more detail:
Another way thought experiments can be used is to prove some claims to be false. When philosopher’s have tried to answer what it means to live a good life, some believe that a good life is one that has as much pleasure as possible and as little pain as possible (known as the hedonistic good life). Philosopher Robert Nozick in his book Anarchy, State and Utopia (1972) asks us to imagine being told that we can live the rest of our lives in a machine that allows us to feel only pleasure and no pain. Nozick anticipates that we would not want to live in such a machine, even though would experience more pain and less pleasure by staying in the real world. So, the hedonistic good life must be false.
The thought experiment operates as a premise in an argument which has the logical form of Modus Tollens, which was covered in the conditionals tutorial:
- 1. If the hedonistic good life is true, then we would want to live in the experience machine (If p then q)
- 2. We would not want to live in the experience machine (not q)
- 3. The hedonistic good life is false (not p)
Nozick’s book can be found here: https://amzn.to/2vtLDdr
Thought experiments can be used in many different kinds of arguments, but the main point to remember is that they do not involve actual observed situations, but imagined situations.
If you wish to ask any questions, seek clarification, raise some objections, or check how you went on the test questions, please write them in the comments section and I will try respond as soon as I can.
I highly recommend ‘An introduction to philosophical methods’ by Chris Daly, and ‘Laboratory of the mind’ by James Robert Brown, which can be found in the links below. If you do purchase these books, you are helping to support this website. Thank you.
Laboratory of the mind:
Introduction to philosophical methods: