I had never heard the term a fortiori before. After looking it up in the two dictionaries I’m using for this project I have a general understanding of it, but I’m still a bit confused on the specifics of its correct usage.
The New Oxford English dictionary bundled with Mac OS X provides the following definition of a fortiori: “used to express a conclusion for which there is stronger evidence than for a previously accepted one.” It then provides an example of, “they reject all absolute ideas of justice, and a fortiori the natural-law position.”
I took from that that a fortiori meant, in essence, “because the evidence better supports it I know accept x as the truth,” whatever x might be. Based on that, I was going to provide the following example of the use of a fortiori: “intelligent people reject the notion of Creation and a fortiori the fact of evolution.”
However, I then looked up a fortiori in The New Penguin English Dictionary (1986). It provides the following definition: “with still greater reason or or certainty — used in drawing a conclusion that is inferred to be even more certain than another.” OK. That sounds roughly the same as the definition provided by the Oxford dictionary.
My problem is not understanding the meaning, but how a fortiori should be used in a sentence because The New Penguin English Dictionary gives the following example: “if he can afford a house, [a fortiori], he can afford a tent.”
If this example is correct usage, it suggests that my use of a fortiori in the example I wanted to give would have been incorrect. Rewording my example to the New Penguin form of the usage of a fortiori it would read, “If creationism is true, a fortiori, evolution is true.” This is, of course, nonsense. Creationism is balderdash, but evolution is almost certainly true.
So, the intended meaning of my original example is correct. I just don’t know how to word it properly. If by some miracle someone reads this and has a better understanding of the proper usage of the term than I do, please share your knowledge in a comment here.