No, they&#x27;re symbols which accurately represent information to us in a useful fashion.<p>Consider a supercomputer simulation of a brain - a completely accurate human mind (ignore the feasibility, this is a gedankenexperiment), which has completely accurate eyes, ears, etc. - a full sensorium. Consider that you place a completely accurate simulated beach ball in front of that mind.<p>You, the external observer, know that this is all just code running on silicon.<p>The mind within the simulation, however, has no concept of outside, however knows itself to be real, that beach ball to be real. This mind could ultimately reason that perhaps it is merely perceiving representations of information in a way that is useful to it. Perhaps this &quot;space&quot; is just information. Perhaps <i>I</i> am just information. I express this to another mind I just met in the simulation, it tells me I&#x27;m nuts, such bullshit.<p>The thing is, it&#x27;s a testable theory, and it doesn&#x27;t require a simulation, either. A holographic universe (totally testable and being tested now) would fulfil the condition he posits, and a simulation, natural or artificial, could too. The simulation argument also applies - if we ever manage to accurately simulate even a small section of a universe even at massive time dilation, it becomes rather likely that this is a simulation too.<p>For all we know our universe exists on the surface of a black hole.<p>So yeah, what we perceive is not &quot;real&quot;, but you can pick at that thread ad infinitum, and it&#x27;s turtles all the way down, so it all becomes a bit epistemologial.<p>That said, there could be useful applications. If it turns out that there&#x27;s another spatial dimension with which our reality is better described (and it appears there is if you like susy, brane&#x2F;M theory, strings) that we can access but only with difficulty so our sensorium excludes it that&#x27;s big news - hyperspace.<p>Edit: just remembered a JBS Haldane quote that applies nicely -<p><i>&quot;Nature is not only queerer than we suppose -- it is queerer than we </i>can <i>suppose.&quot;</i>