I spend a lot of time in a (mostly futile) effort to get conservatives to back up their claims with facts. Most rightwingers react with shock and dismay when I ask them for the evidence for their claims: Whaaaat? You want facts? Everything I say should be considered Gospel simply because I say it. Go look up the facts that I am sure will support my claims yourself, you goddamn Commie faggot.
John Scalzi lays out, in achingly concise prose, exactly why facts are essential to a good argument, and why demanding facts is not a partisan act:
1. One is entitled to one’s own opinions, but not one’s own facts. Commensurately, anecdote may be fact (it happened to you), but anecdote is usually a poor platform for general assertions, since one’s own experience is often not a general experience.
2. If you make an assertion that implies a factual basis, it is entirely proper that others may ask you to back up these assertions with facts, or at least data, beyond the anecdotal.
3. If you cannot bolster said assertion with facts, or at least data, beyond the anecdotal, you have to accept that others may not find your general argument persuasive.
4. This dynamic of people asking for facts, or at least data, beyond the anecdotal, is in itself non-partisan; implications otherwise are a form of ad hominem argument which is generally not relevant to the discussion at hand.
5. If you offer evidence and assert it as fact, you may reasonably expect others to examine such information and to rebut you if they find it wanting and/or find your interpretation incorrect in some manner.
All of which is to say that asserting from anecdote without being able to bolster said assertion with actual facts is likely to get your assertion discounted; if you present facts without rigor, you’re likely to see those discounted as well. Again, this is neither here nor there as regards one’s personal politics; this is simply about making a robust argument.
Next time a wingnut reacts with hurt and outrage after I’ve pointed out he needs to back up his spew with evidence, I’ll just lay a little Scalzi on his fact-challenged ass.