Ultimately, if our minds are unreliable and reality as we understand it is simply a shared hallucination, does it matter? If what you see as a table is the same thing everyone else sees as a table, would it make a difference if the object were actually a chair? While this example is an over-simplification of the problem, it's a good illustration. If our perception of the world depends entirely upon our interpretation of sensory input, doesn't that make it reality to us?
A pragmatist might say that without being able to step outside the human experience and perceive reality in an objective way, it's impossible to say if what we think of as real is representative of true reality. There's no way we know of to wake up from the shared dream or emerge from the matrix. That could mean we're permanently stuck in an illusion or it could mean that our perceptions actually match up to reality and there's no illusion there in the first place. Perception and reality are the same as far as we're concerned.
Meanwhile, we're making progress in creating virtual worlds in the technological sense through multiple paths. Computer engineers, technologists and psychologists are designing virtual environments that mimic real situations and can provide a real sense of immersion. While subjects in such a virtual environment might not think of the world as being real, they do tend to learn the rules of the virtual environment and adapt to them. The subjects begin to behave in the world as if it were real -- even going so far as to have real physiological reactions to virtual stimuli. But most are still fully aware they exist only in a simulation.
We're also seeing developments in the field of augmented reality. With augmented reality, we create an overlay of data and interactivity on top of the world we perceive around us. Using devices like smartphones, we can view the world surrounding us and access additional data. A good example of this is the Monocle feature in the iPhone app Yelp. As you point the iPhone's camera toward businesses, reviews pop up on the screen. Your perception of the world is augmented instantly.
As we find new ways to perceive and interact with the world around us through technology, we may further divorce ourselves from reality. In fact, we feel safe in saying it's a virtual certainty.
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