aka reductio ad absurdum - the premise that something impossible is actually true, and then proving it is ludicrous
All women have blonde hair, which is false when you present a woman with brunette or red hair
One of the basic logical fallacies is the reductive fallacy, or in Latin, 'reductum ad absurdum'. Basically means taking a normal argument to such a far extreme (reducing it in an absurd manner) as an attempt to try to say it is wrong.
Note this is a logical fallacy. Just because one can think of some far out case.
Look man, if I give you $5 today then I'll have to give you $5 tomorrow, and then I'll be out $5 a day for the rest of my life.
an error of reducing higher or more complex processes, such as human behavior and thinking, to its elementary components or material bearers, such as physiological structures or chemical reactions.
Reductive fallacies abound in the popular works of Carl Sagan. For example, he wrote in his best-selling book The Dragons of Eden": "My fundamental premise about the brain is that its workings--what we sometimes call "mind"--are a conse`uence of its anatomy and physiology and nothing more".