On the contrary, it is very common for people to feel the emotion of love when the object of their emotion has a completely different emotion. This is even more true of jealousy, when imagined trespasses are quite common. This shows the emotions are NOT caused by an exterior force, but are internally induced (although sometimes triggered by external events).<quoted text>
They are internal experiences caused by an exterior force.
It's pretty hard to fall in love with nothing or be jealous of nothing.
I'd even go so far as to say that people many people are 'in love' with partners that have little to do with the *actual* person. Instead, they are imagined entities conforming to some ideal that the real person would not recognize as being themselves. Now, this type of self-delusion probably decreases with experience, but I do think it is quite common. The phenomenon of 'putting someone on a pedestal' is a classic example.