If 'something' is never observed can it exist?

It is also believed therein that any well-defined application of the quantum mechanical formalism must always make reference to the experimental arrangement. This is due to the quantum mechanical principle of wave function collapse. That is, a wave function which is initially in a superposition of several different possible states appears to reduce to a single one of those states after interaction with an observer. In simplified terms, it is the reduction of the physical possibilities into a single possibility as seen by an observer. 

This raises philosophical questions about whether something that is never observed actually exists

Source: Boundless. “Philosophical Implications.” Boundless Physics. Boundless, 26 May. 2016. Retrieved 31 Jul. 2016 from https://www.boundless.com/physics/textbooks/boundless-physics-textbook/introduction-to-quantum-physics-28/history-and-quantum-mechanical-quantities-182/philosophical-implications-675-6347/

Source: Boundless. “Philosophical Implications.” Boundless Physics. Boundless, 26 May. 2016. Retrieved 31 Jul. 2016 from https://www.boundless.com/physics/textbooks/boundless-physics-textbook/introduction-to-quantum-physics-28/history-and-quantum-mechanical-quantities-182/philosophical-implications-675-6347/