"So, what if he is wrong and you know that you're right? Listen to what he has to say and try to understand why he raised that objection. Perhaps, there's a gem hidden beyond the surface."
That is an interesting piece of advice. Credit yourself in areas that you are capable but be humble to recognize your weaknesses, and you'll have a clearer picture of whether you can make it on your own.
In the words of Sun Tzu, "If you know your enemies and know yourself, you will not be imperiled in a hundred battles."
Before entering university, I had an applied research project that generated visitor passes by performing OCR on identity cards. The idea was to use them for protected locations as a better alternative to leaving your precious identity card at the security post. It worked but never went anywhere because I didn't know how to do very much algorithmic analysis and design work and didn't have the confidence to sell what I had simply put together by experimentation.
Now I do a lot of algorithmic analysis and design but see my research work as too difficult to commercialize. Ironically, my current startup idea doesn't have academic research behind it as a competitive advantage... It's just a service that I know people want.
Good to have some positive examples where academic research helps rather than hampers the startup... It strikes me that the profile of a person who does research doesn't seem to fit too well with the image of a young entrepreneur who wants to translate ideas to the market as quickly as possible. Albeit both require a hell lot of perseverance ;)