Why does the argument "I've used math to justify my views, so it must have some validity" tend to override "Garbage In - Garbage Out"? It can be this thread:

I estimate, that a currently working and growing superintelligence has a probability in a range of 1/million to 1/1000. I am at least 50% confident that it is so.

or it can be the subprime mortgage default risk.

What is the name for this cognitive bias of trusting the conclusions more (or sometimes less) when math is involved?