Only and Causal/Non-causal argument comparison

[voodoochild]

Instructors,

I was reading through the PB book again just to make sure that I am okay with basics esp. with causal reasoning/non-causal reasoning and "the only" factor mentioned on page 203

Let's say the conclusion (non-causal) is "The Republicans will be able to gain votes in the presidential election, only through honest campaigning and not through television advertising."

In my opinion, the author is specifically stating that "honest campaigning" is the only way to gain votes in presidential election. Hence, a statement that says that republicans can gain votes by placing ads on YouTube would weaken the conclusion. Correct?

On the other hand, had the author said, "The Republicans will be able to gain votes in the presidential election, through honest campaigning and not through television advertising." The same statement "republicans can gain votes by placing ads on YouTube would weaken the conclusion" wouldn't weaken author's conclusion at all because the author isn't saying that "honest campaigning" is the only way. He has left open other possibilities. In fact, "...placing ads on Youtube" would be considered irrelevant. On the other hand, if I modify the statement to say that "Republicans' placing ads on YouTube will increase their chances of gaining votes more than other sorts of compaigning" would weaken the conclusion. Am I correct?

The reason why I have introduced "personal" argument is that the book recommends that we personalize the arguments. It really helps me and my study-group.

Thanks again in advance.

[Adam Tyson]

What you have here is a conditional argument, with the key indicator word "only". The best (perhaps the only?) way to weaken a conditional argument is to demonstrate that sometimes (at least one time) the sufficient condition happens when the necessary does not happen.

In your example, I'm not sure that saying you can gain votes through a YouTube ad weakens the conclusion that "the only way to gain votes is through honest campaigning", because the two are not mutually exclusive. Couldn't the YouTube ad be a form of honest campaigning? The diagram "Gain Votes -> Honest Campaigning" isn't weakened by the sufficient condition (gaining votes) occurring and some other condition "YouTube ad" also occurring, unless we know that the necessary condition ("honest campaigning") did NOT happen. A weaken answer here would more likely be "John did not run an honest campaign, but he gained votes".

As to your later example, I don't think that YouTube being a better way does anything to weaken the argument that they will gain votes through honest campaigning and not through television advertising. To weaken that statement, I think you need to directly attack the conditional relationship with "they ran an honest campaign and gained no votes" or perhaps "they ran a dishonest campaign and only ran tv ads, and they gained votes."

Directly attack the conditional by saying the necessary condition really isn't necessary. That will weaken, whereas merely offering an alternative to the stated relationship won't help.

Adam