(April 16, 2009 at 3:48 pm)Eilonnwy Wrote: which is that the person making the fallacy must first make their own definition of what it is to be a true scotsman or christian.I disagree. I think you can have a No True Scotsman fallacy without first making the definition, because often the definition is implied through the fallacy. For example, say a Christian and an atheist are both watching a news report of a preacher who shot his congregation. The atheist might say "see, Christians can do evil things too". If the Christian responded "That preacher wasn't a true Christian, no true Christian would do that" then they are making the fallacy.
The only time when a no true Scotsman is not applicable is when the action is directly connected to the meaning of the word. Like the wiki article says, "No true vegetarian eats meat" is perfectly true, so is "No true atheist believes in gods". Vegetarians are defined as people who do not eat meat, and atheists are defined as people who do not believe in gods.
If "Christian" was defined as "person who does not shoot people" then the above example of the church shooting would be true. The preacher wouldn't be a "true" Christian. However the definition of a Christian is one who follows Christ, or believes in the doctrines of Christianity.