A Guide to Practical Debunking

Mick West

Administrator
Staff member
I think that it is important that people understand the difference between Inductive Reasoning and Deductive Reasoning and why Metabunk relies on Deductive Reasoning in examining claims.
I disagree. I think a lot of what we do here is more commonly abductive reasoning, briefly mentioned at the end of your post. Although I don't think their explanation is very good.

But really "reasoning" is sometimes too high level a descriptor for what goes on. Quite often it's just "fact checking".
 

Critical Thinker

Senior Member
I disagree. I think a lot of what we do here is more commonly abductive reasoning, briefly mentioned at the end of your post. Although I don't think their explanation is very good.

But really "reasoning" is sometimes too high level a descriptor for what goes on. Quite often it's just "fact checking".
You are right, I had originally in the post not included the Abductive Reasoning part and after further investigation corrected my oversight and included it in my post. Thank you for the clarification, I have fixed my misstatement accordingly. :)
 
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Mick West

Administrator
Staff member
Deduction, as in deductive reasoning, is figuring out a conclusion given some facts (premises). The problem with deduction is that it relies on those premises being true. A large part of what we do here at Metabunk is actually examining those premises and figuring out if the premises are true.

For example, a deductive process might go like this:

1) Jet fuel burns at 1500°C
2) Steel Melts at 2500°F
3) Molten steel was found after the WTC's collapse
4) Therefore something other than jet fuel was burning in the WTC, something that burned above 2500°F

The debunking process here is mostly fact checking. We can verify #1 and #2, but there's no evidence of any molten steel being recovered from the WTC site. So #3 is not valid, hence #4 is not valid (not proven false, just not supported by evidence). The deductive steps are trivial.

#3 ("Molten steel was found after the WTC's collapse") is actually something that people infer from eyewitness accounts. The deductive process goes like:

5) Firemen working at ground zero said they saw molten steel
6) Firemen have no reason to lie
7) Therefore there was molten steel at ground zero

Now here we can use deduction (pointing out that thinking you saw something is an inadequate premise for proving what it actually was, something that looks like molten metal is not necessarily steel), inference (eyewitnesses often make mistakes, so this might have been mistakes), and abduction (what's a likely source of someone thinking they saw flowing molten metal, given what was in the building and the heat that fires normally reach? Aluminum, lead, glass? Rank the possible explanations)

Deduction is often lauded as part of the investigative process, but I think it's a bit overrated, it's more a way of formally making an argument than it is a process for figuring something out.
 
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