Mary, I hope you don't mind, I think I am going to get that little gem printed onto a T shirt
Not in the least! It's wise to caution against dualism -- it's definitely a prevalent thought mode these days, to the point where I'd call it a learned reflex. But logic is a tool that is used to arrive at the truth, and while the truth is sometimes a single discrete thing, that's not dualism...that's just, ya know, the truth. Two plus two IS four; that's not dualistic thinking. And just as often, the truth that logic brings us to is, "Could be this, could be that, could be the other, could be possibilities as yet unimagined." If you believe that logic = dualism...you are indeed doing it wrong.