This was a very interesting article and the author makes a strong argument for Isaac Newton. I think that it is very likely that the smartest person whoever lived is / was not even well known to the public. Brilliance is no guarantee of great success. Even Nikola Tesla who did a lot more than just pioneer our entire modern electric grid very nearly died in his youth. His inventions and might have never been developed without the proper economic conditions and a lot of luck. If he had been born 25 years earlier it is likely that his inventions likely would not have come to fruition. He could very well have died a penniless old eccentric... oh that is right he did.