Arousal is a physiological reaction. An urge in my opinion is your brain planning / rationalizing further action(s) based on thoughts or desires. “They had an urge to do x or y.” 

If we want to have a real philosophical conversation we should define the words we’re using out the gate so we’re not talking past each other. 

Blink is a book about the power of the instinctual “brain” which makes the case for it being incredibly clever and powerful and able figure things out in one second that your thinking brain will likely never figure out or in many cases lead you further from the best decision.