Logic
Excerpt taken from the Logic online course given by Carnegie Mellon University:
We have discussed how to identify an argument, and its premises and conclusion. We haven’t discussed yet what makes an argument a good argument. Since an argument can be construed as a reason to accept the truth of its conclusion, we will consider an argument a good argument just in case it represents a good reason to accept the truth of its conclusion — that is, just in case we really ought to believe that the conclusion is true, based on the argument alone.
EXAMPLE:
——————————————————————————–If you don’t remember to keep the lid on a teapot when you are finished using it, cats are likely to get into the teapot and make a mess.
=> You should remember to keep the lid on a teapot when you are finished using it.
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Assuming that you did not remember to keep the lid on your teapot, there is not much of a chance that you will need to worry about cats getting into it — to begin with, most cats wouldn’t fit into a teapot (unless you had an awfully large teapot). Given this, you probably wouldn’t consider the premise of this argument to be true. Even if you did, however, you might be the sort of person that would find a cat in a teapot vastly amusing, regardless of the mess, and hence encourage that sort of behavior from your feline friends. The premise of the argument is not true, nor does it provide particularly strong support for the conclusion. As a result, it is not a good argument.
How about our second example:
EXAMPLE:
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Cats don’t like to get wet, and teapots are frequently filled with tea.
Immersing a cat in tea is guaranteed to get the cat wet.=> Cats are not likely to get into teapots.
——————————————————————————–
In contrast with our first argument, the premises of the argument are all true — cats really don’t like to get wet (at least most of them don’t, though there is the odd cat that even likes to swim), teapots are frequently filled with tea, and immersing a cat in tea will get the cat wet (and probably mad at you as well). These premises also provide at least some support for the conclusion—any cat that had the good sense to check the contents of a teapot before climbing in would probably be dissuaded from doing so by the presence of tea in the teapot. Of course, not all cats have good sense, particularly those still of a size to fit into a teapot. So there could be the odd cat in a teapot, though probably not enough of them that cats in teapots could reasonably be considered a likely situation. This argument is thus a fairly good one.
Ah, there is nothing like basking in the beauty of Logic as taught by CMU professors!
