Fred Alan Wolf, PhD looks into what quantum physics tells us about the nature of reality, specifically the parts of reality we do not directly perceive, so-called called ‘hidden variables’? It shows that what we observe can actually change depending on what else is revealed along with it. This contrasts strongly with what we experience in our everyday lives. Quantum correlations cannot be explained assuming that the result of a test C is independent of whether C is performed together with a compatible test B or with a compatible test A (which may be incompatible with B). Thus, quantum physics shows that our common sense notion that what we observe does not depend on what else we observe along with it is wrong. Contrarily, change the “what else” e.g., the context, and the observation itself changes. Many experiments have been performed confirming that, indeed, observations can and do change depending on what else is observed along with them. This result might have been expected since the uncertainty principle tells us that we cannot observe certain pairs of observables, such as momentum and position, of an object simultaneously. But these contextual considerations go much farther than that, for they consider observation of things that normally can be observed simultaneously without changing. Such observations do not follow as our classically intuitive consideration would dictate – they are dependent on what other observations are made with them. What we see may not at all be what is “really out there,” but instead may be dependent on what else has been observed, even if not by us. We conclude that if quantum physics applies to real-world observations, the world cannot be a classical one – what we expect to see in it can, and does, depend ultimately on what context one includes in one’s observations as well as one’s expectations and worldview. I believe this adds credence to the notion that it would be more fruitful to consider the “out there” as a product of the “in here.” In other words, quantum physics is telling us that the universe is a mental construction after all.