"I didn't know it was impossible, so I went ahead and did it."
Knowledge can pave the way for even greater progress, but sometimes knowledge can become a dogma (a principle or set of principles laid down by an authority as incontrovertibly true). When you are told that the parameters of possibilities are limited, that knowledge inevitably directs your thinking and actions within the possible areas.
This is especially true in some societies where authority is deemed as the final word, either due to respect or genuine belief in the dogma. When someone authoritative or senior says that this is impossible or ridiculous, people tend to concur and consider options or actions in the realm of "possibility". With the advent of the internet and online forums, this phenomenon becomes ever more acute, with some individuals lording over the online discussions and perpetually dominating the forums with their opinions and silencing dissenting voices with their mastery of the language or sheer dedication to posting lengthy verbiage and discussion beyond what others are willing to commit. Such individuals may not be truly knowledgeable in their fields, but their voices are loud enough for them to perceived as the authority. Their advice might not be correct, but many would be willing to listen to their 'advice'.
The rise of the online community raises another ugly head - which is that of the lazy individual who scours forums/websites for the answer. Rather than trying out the hypothesis to discover the answer, many turn to the keyboards to seek the wisdom of the masses. While searching online certainly can harness the power of other users, many important discoveries in the history of mankind run counter to the beliefs and common sense experience of the masses.
The online forum said, "That darn thing can never fly!" Yeah right...
Had the Wright brothers gone online to seek opinion of their plane design, they would be derided by the others in the men-can-fly.com forum (fictional of course). Had Eratosthenes conferred with Homer (an authoritative figure in ancient Greece, not the Simpsons!), he would have laughed at his own notion that the world could indeed be round (the Greeks believed the world was flat, and that you'd sail off the edge of the world if you go far enough!). Galileo Galile didn't believe the Catholic Church authorities and challenged their "truth" that the Earth is the centre of the universe.
The point is this - if you didn't know that it cannot be done, you will attempt to do it. It may sound foolish, but the fact is that many "truths" are not scientific or empirically impossibilities. When someone says something cannot be done, think whether the statement was in fact referring to "probabilities" or based on nothing more than the experience of the masses. The next time when you hear that something is impossible, perhaps it's better to turn a deaf ear. If you listen only to the masses and ignore your inner voice, you will only be as good as the masses. Ignorance can be bliss.