<p>““In spite of all that I have said above, those two pieces gave me an eerie feeling.””</p>
<p>More on these eerie stuffs. :-)</p>
<p>Bostrom’s argument is the cleanest I know of, in favor of a grand simulation which canbe nested within infinite layers of other simulations. He is being conservative to estimate that,
“In the dark forest of our current ignorance, it seems sensible to apportion one’s credence roughly evenly between (1), (2), and (3).”,
because there is no particular time limit to break the threshold of (1), except for the lifespan of civilizations and there is no particular reason to support (2), which leaves the most probable outcome to be (3), i.e. we are likely living in a grand simulation.</p>
<p>So how close are we toward breaking the threshold of (1)?
“The IBM research shows that a model of the human brain—which has 20 billion neurons connected by about 200 trillion synapses—could be reached by 2019, given enough processing power.”, [IBM</a> Unveils a New Brain Simulator - IEEE Spectrum](<a href=“http://spectrum.ieee.org/computing/hardware/ibm-unveils-a-new-brain-simulator]IBM”>IBM Unveils a New Brain Simulator - IEEE Spectrum) ,
which suggests that grand simulations of entire civilizations may only be several decades away, if we weren’t going to kill ourselves first with a WW3. Even today’s computer games are employing simulations with real physical laws, [PhysX</a> - Overview - GeForce](<a href=“http://www.geforce.com/Hardware/Technologies/physx]PhysX”>http://www.geforce.com/Hardware/Technologies/physx) .</p>
<p>A further extension to breaking the threshold of (1), is to let simulations self-improving and evolving into who knows what. Also from Schmidhuber,
“This inspired my Gödel machine — an agent-controlling program that speaks about itself, ready to rewrite itself in arbitrary fashion once it has found a proof that the rewrite is useful according to an arbitrary user-defined utility function (all well-defined problems can be encoded by such a utility function)… Gödel machines and the like will rapidly improve themselves and become incomprehensible.”.
Schmidhuber has also been trying to address the issues of consciousness and sentience,
“We have ongoing projects based on a simple principle explaining essential aspects of subjective beauty, novelty, surprise, interestingness, attention, curiosity, creativity, music, jokes……”, [Build</a> An Optimal Scientist, Then Retire](<a href=“http://hplusmagazine.com/2010/01/05/build-optimal-scientist-then-retire/]Build”>Build An Optimal Scientist, Then Retire – h+ Media) .</p>