Richard Feynman explains some of the key points to scientific reasoning. This is the best way that we have for evaluation of claims. If you notice it is somewhere between induction and abduction, but the key point is the testing against experiment. This testing is how we form impressions of the world, that we can say are correct (for a given value of correct).
He also demolishes the appeal to authority, citing the test against evidence as the only arbiter of fact vs fiction.
He then goes on to discuss the idea of proving or disproving something. And states the pragmatic idea: "We must always try to guess the most likely explanation keeping in the back of the mind that if it doesn't work, we must discuss the other possibilities."
The importance here is that we can think of this process as an effort to define and eliminate types of ignorance. We can attempt to explain the world, but our statements of absolute certainty must be reserved for what has been repeatedly shown to be false. Other ideas must be discussed in a manner of what the limits to the information we have are, and what test would prove our idea conclusively wrong.
This is not to discount positive evidence or say that we can know nothing, it is only to temper our claims of certainty with doubt. And while there may be some indication that we humans favor the certain over the uncertain and flock then to demagogues, we can train ourselves through understanding and vigilance to resist this baser impulse.
This link contains some great quotes from scientists as they struggle to define the term science. Which is the process that I attempting to describe here. An idea that is so simple that it almost refuses clear definition. But following through on defining terms so that we may be understood is a goal of those that wish to discuss things clearly, without retreating to fallacies or vague assertions.