What is a man if not the sum of his prejudices.

What is a man if not the sum of his prejudices.
Can’t remember where I read this line but it has been going around in my head for many years now. I sometimes like to imagine that I made it up – mostly because I think it would by far be the most beautiful thing I have ever created. I can’t think of a single thing that I have created which is likely to have given joy to someone. My writing is laborious – I have many ideas – some original most inspired - but really struggle to put in down in words in any meaningful way -- forget about in beautiful words. Hell – I can’t even spell and think the spell check on Microsoft word is a modern day great invention.
Every time I am shocked at prejudice of any kind – or what I call irrationality since I can’t understand how rational people can have strong prejudices especially since it is not rational to be so, and have finished railing against it, I think of this line and realise that it is these very prejudices that makes each individual what he/she is. That is what makes them function, create, react and distinctive.
I have actually run out of anything else to say on this topic – explains why I am such a bad writer and awful at creating anything. However, if anybody has ever come across this line before –please let me know so that I can shatter the myth I have built that I created this line and prove to myself that I can never have created anything that is so original and beautiful or maybe I think it is so beautiful and original because I think I created it.