We assume that what we see is what is...but...

physics today is increasingly about quantum states that are patently not physical at all. 

So whether the virtual reality conjecture is true or not, science can still flourish. 

We can still test theories if the physical world is not real, as long as it is an interface to reality. 

Likewise the earth is “solid” to us who are made of the same stuff but to a speeding neutrino from the sun our whole planet is just a ghostly shadow through which it flies.

We assume that what we see is what is, but it could be generated on demand when we look, just as quantum theory says it is.