February 22, 2013 by mattfradd
In a previous article I explained what an argument is (and is not). Some have asked what constitues a good argument. Here are three things which constitute a good argument.
1. Clear Terms
The first thing which constitutes a good argument is clear terms. Terms can be used in equivocal senses; for example: 1. All feathers are light, 2. That which is light cannot be dark, 3. Therefore feathers cannot be dark. In this case, the first premise usage referred to weight, while the second premise used the term to refer to that which makes things visible.
2. True Premises
The second thing which constitutes a sound argument is true premises. You can “prove” anything from false premises: 1. All unicorns are infallible, 2. My son is a unicorn, 3. Therefore my son is infallible.
It might surprise you to know that that argument is logically valid, that is, the conclusion follows logically and necessarily from the premises; the only problem is that the premises are false!
3. Valid Logic
Thirdly, and finally, an argument needs to be logically valid. That is, the conclusion must follow from the premises according to the laws of logic. Here is an example of an argument which has true premises but invalid logic: 1. Snow is white, 2. Paris is the capital of France, 3. Therefore a Beaver is a broad-tailed, semi-aquatic rodent.
You don’t need a Ph.D. in philosophy to recognize that the conclusion, “a Beaver is a broad-tailed, semi-aquatic rodent,” does not follow from the premises.
Finally, it needs to be noted that in order for an argument to be a good argument, it does not have to yield 100% certitude. If the terms are clear, and the argument is logically valid, then you might ask yourself, are the premises more plausibly true than not.
Perhaps, when assessing the Kalaam argument for the existence of God, you’re unsure whether the premises are true or false. In that case you should ask yourself, are the premises more plausibly true than their negation. So, is it more plausibly true than false that (Premise 1) Whatever begins to exist has a cause? And is it more plausibly true than false that (Premise 2.) The universe began to exist? If you answered yes to both questions, then you should accept that (Conclusion) the universe has a cause.