The question of observer is an interesting one in science and in particular in physics ever since Nobel prize winners made some observations regarding observing the particle and its momentum both cannot be seen at the same time and secondly the concept of collapse of the wave function when an electron is observed it collapses from its wave form to particle. Average human being thinks he is observing everything with his physical eyes. There are many who aver that human brain with the material science view is observing since science believe human brain is the seat of human consciousness.
I have opened up more details from sub quantum level since even Copenhagen interpretation was incorrect. Behind human physical eyes is the all seeing eye of Quantum Code which is the seat of human consciousness inside human brain. It is this i.e. Quantum Code consciousness (my scientific discovery) which is observing human brain and body. This is the beautiful truth. Trouble is science cannot see that yet, as they have not reached their observing power from sub-quantum level when you are in finest aspects of reality not visible to physical human eyes or human brain. Consciousness is the key as entire Universe is beautifully conscious from this level of source of Universe consciousness and human origins.
This is yet beautiful example of Intelligent Design.