When I ask people to do this in person they will often refuse or dodge the question.
When someone says a word of which I do not understand what substance they are referring to like "faith", "god", or "spiritual", how do I ask them what they mean in such a way that they will tell me?
If someone refuses to define their terms, this is evidence that they either do not understand the concept well or that they are not interested in rationally changing your mind. If you think the former is a better description, then pointing out that the definition is inadequate is the best response. Practically, you should try to avoid using tones that make this sound like a "gotcha" question. If you are genuinely confused, you should be able to express that fact.
If you think the latter is better description (i.e. the debate partner is using a semantic stop sign or similar maneuver), then your best action is to terminate the debate. You won't make any progress until your debate partners are willing to engage the issues, especially any weaknesses in their arguments.
In short, you can't force people to define their terms. You can point out the failure to provide definitions, or you can leave.
I'm about to be traveling for approximately a week, and I am not very confident that I will have much in the way of internet access. Therefore, this rerun post will be my last until (I expect) next Monday.
Today's post, Replace the Symbol with the Substance was originally published on 16 February 2008. A summary (taken from the LW wiki):
Discuss the post here (rather than in the comments to the original post).
This post is part of the Rerunning the Sequences series, where we'll be going through Eliezer Yudkowsky's old posts in order so that people who are interested can (re-)read and discuss them. The previous post was Taboo Your Words, and you can use the sequence_reruns tag or rss feed to follow the rest of the series.
Sequence reruns are a community-driven effort. You can participate by re-reading the sequence post, discussing it here, posting the next day's sequence reruns post, or summarizing forthcoming articles on the wiki. Go here for more details, or to have meta discussions about the Rerunning the Sequences series.