>>Why settle for what works better? I want what works best.

Usually this is achieved by considering evidence before reaching a decision. It may be easier to declare a position and then block any evidence that conflicts with it, but that sort of Soviet thinking doesn't lead to best results as has been proven through history. The reality is that nobody really can be sure and if debate turns into fortified positions over whose walls people toss grenades at each other, the result always will be less than it could be.

>>Problem : I cut my finger...

A better analogy might be:

Problem: I cut my finger
Solution: I know for sure that tourniquets are useful in injuries, so I apply one to my finger
When the finger falls off, I declare that the tourniquet saved my arm that would have fallen off had I not used the tourniquet.
If somebody tries to suggest that there might have been better treatment options, I declare that this is irrelevant because history has shown repeatedly that tourniquets not only save limbs, they save lives.