[garycooper]

If you can prove the existence of love, please be my guest!

[billybudd]

I love my cat. There we go. If I define love as a certain feeling I have towards something, then it's easy to prove, because all I have to rely on as evidence is my feelings. However, God is not a feeling and therefore cannot be proven by feelings.
BTW, I was only half serious when I said science can prove everything. Science can prove the existence of physical objects or physical processes. To the extent that love is defined as a physical process, it can be proven to exist. It's a chemical reaction in your brain, etc.