This article aside, it isn't. This idea stems from Cartesian methodological doubt which is the death knell for all knowledge. Methodological doubt is irrational

This article aside, it isn't. This idea stems from Cartesian methodological doubt which is the death knell for all knowledge. Methodological doubt is irrational. It is not rational to doubt things for no reason. You must have a reason for doubting something just as you must have a reason for believing something. Irrational doubt cannot be overcome through reason precisely because its genesis is not in the intellect, but in the will. It is arbitrarily assigned to something and so you cannot rationally resolve the cause of the doubt one way or another because there is no rational cause to resolve. Rational doubt is the result of coming to know something credible that contradicts or undermines something you take to be true. This casts doubt on your prior belief. To resolve it, you must verify your prior belief and/or the new information.