A (MLM) Skeptic: Bad Argument: Absence of Evidence / Argument from Ignorance

Sunday, May 26, 2013

Bad Argument: Absence of Evidence / Argument from Ignorance

"Absence of Evidence is Not Evidence of Absence"
CSI: Crime Scene Investigation
(season 2) (Photo credit: Wikipedia)

When supporters of a suspicious scheme ran out of defenses for their particular scheme, they will often trot out the "absence of evidence" as somehow proving that their scheme was not a scam. There are several variations on this theme, such as:

The company was never charged with a crime!
The company was never investigated!
The company only has insignificant number of complaints!
and so on and so forth

This is the inverse of the bandwagon fallacy. In bandwagon fallacy, a large number of people believe in the idea and somehow this is construed as into "numbers make it true". The inverse is "lack of numbers makes it false".

In critical thinking, this is known as "argument from ignorance", though it is often misunderstood or misinterpreted, because "ignorance" here means "absence of evidence to the contrary".

Those who watch CSI or related shows may remember one of the crew say something to this effect:

Absence of evidence is not evidence of absence

Wikipedia gave the following example: imagine a person in a house with a tin roof. Upon hearing no rain on the roof, he declared it is NOT RAINING without looking out the window, even though it had been drizzling. Absence of evidence (sound of rain on tin roof) is not evidence of absence (of rain).

Or in case of CSI, just because you didn't find certain evidence of the suspect at the scene, doesn't mean he was NOT there. (There may be other types of evidence you didn't look for).

In the case of suspicious schemes, absence of record of wrongdoing does not prove there had been NO wrongdoing.

There could be no record of wrongdoing for several reasons:

The investigation is still ongoing (investigation often takes years, and not always public)
The company was too new (just opened weeks / months ago)
The company settled the complaints behind closed doors and sealed them with NDA
Arrest, prosecution, and conviction takes time
The records were sealed as part of a plea deal
and so on

Supporters of suspicious schemes will often follow this with its variants

One variant is the "It's legal until it's convicted" bad argument, where supporters try to claim "presumed innocence", i.e. a business is presumed legal until declared illegal, never mind all the evidence in their face. They are confused as to the definition of "illegal" vs. "convicted". One can have done illegal things without being convicted.

Another variant is often used when the supporters were confronted with evidence of wrongdoing by the suspicious scheme in a different location. This one is known as the "they did it wrong" argument, as in "those who got caught must be doing it wrong (and we're doing it right)", without even asking if that other group did anything differently.

This argument is frequently followed up by "moving goalpost". It goes often like this

You explain this thing is illegal.
They say "show me the proof"
You give them proof.
They say "so what, that's just you."
You show them government investigation.
They say "so what, investigations are common."
You show them conviction in another country
They say "so what, they must be doing it wrong (we're not)"

Note the moving goalpost... First it was "show me proof", then "show me investigation", then "show me conviction". They lost three times, and they simply step a few steps back and demand the other side to prove it all over again.

It is very easy to fall into this sort of logic trap, into thinking that absence of evidence of wrongdoing is somehow indicative of how "legal" the company is. Don't fall for such trick.