 For a particle of spin-1 the problem is even more severe. The components of spin in different directions aren’t simultaneously measurable. Thus, the impossible vector relationships for the spin components of a quantum particle are not observable. Bell (1966), and, independently, Simon Kochen and Ernst Specker (1967) showed that for a spin-1 particle the squares of the spin components in the various directions satisfy, according to quantum theory, a collection of relationships, each individually observable, that taken together are impossible: the relationships are incompatible with the idea that measurements of these observables merely reveal their preexisting values rather than creating them, as quantum theory urges us to believe. Many physicists and philosophers of physics continue to regard the  Kochen-Specker Theorem  as precluding the possibility of hidden variables.