Appeal to probability


 
This fallacy works in an argument by asking, is X possible? The goal being to force the other person to concede that it is possible and then to apply the common sense logic that something that can happen will happen. The fallacy in the argument is that concluding that it will happen implies that you should act accordingly. A humorous example of this is Murphy's Law: Anything that can go wrong will go wrong.  What the fallacy ignores are the frequency, impact, and timescales. If something is possible but very unlikely (a once in a thousand year event) then for practical purposes you should not conclude that it will occur in your one year project.
 
Name of fallacy Appeal to probability
Aliases  
Type Deductive Logic Arguments, Formal Argument
Description Assumes that because something could happen, it is inevitable that it will happen.
Example "There are many hackers that spread worms through the internet. Therefore, if you use the internet without a firewall, it is inevitable that you will be hacked sooner or later."

While using a firewall is a prudent and sensible measure, it is not inevitable that a hacker will attack an unprotected computer. The argument does have some backing logic but overstates the worst case scenario.

FormThis argument has the form:
Possible P,
Therefore, P
Treatment The argument is mathematically flawed. There is always a chance that P will not occur, and therefore, no proof that P will occur given its probability.