I don't buy into the 'chemical computer' theories as it simplifies things far too much. Indeed our brain is made up of complex chemicals and neurons and synapses that work to process information very similar to a computer.However a computer, regardless of complexity, is a device of pure logic. It is fed data, processes it and comes out with an answer or end result. As long as the data stays the same and the program is unchanged, the answer is always the same. With humans another factor comes into play...self awareness. Negative and positive feedback systems no longer hold sway as being a contrary creature, humans can make decisions outside of the normal parameters of a situation based on abstractions and concepts and even emotions. Sure, evolution has ensured much of our makeup is based on logical constructs of survival, but somewhere along the line we became something more. Consciousness and self awareness take us beyond the realm and predictability of standard systems. Moral and ethical concepts and emotions such as love are much more than a chemical reaction, they are part of our transcendence to something greater.
Enter religion, the soul, and devine intervention. People used to say the earth was flat and that it was at the center of the universe, and thunder and lightning were a sign the gods were angry at you. Over time explanations for things seen first as supernatural trend toward explanations based on scientific theory and proof.
http://en.wikipedia.org/wiki/Love_(scientific_views)
