From: Sent: To: Subject: Thx perfect jeffrey E. <[email protected]> Sunday, August 14, 2016 12:00 PM Re: On Sunday, 14 August 2016, =MI < <mailto »= wrote: Jeffrey, there are several sides=to this: 1. Computers that are technically different from our current digital comput=r architectures, but can do the same things, because they can mathematical=y be proven to be equivalent, and we can build a digital equivalent. Examp=es are computers with ternary logic, neural networks, factor graphs etc. 2. Probabilistic computers: instead of deterministic state transitions, the= change state with a certain probability. We can get them to approximate d=terminism with arbitrary precision by stacking the probabilistic gates. Ma=y cognitive scientists and Al researchers believe that brains are in that =ategory. (We can also reproduce their behavior on a digital computer by ad=ing random noise.) 3. Computers that are technically different from our current digital comput=rs, but are still mathematically equivalent, yet it may not be practical t= build a digital equivalent, because it would be too large or too slow. Ex=mples are DNA computers, chaotic computers etc. Digital physicists I believe that even the universe is in this category. thinks the brain is in this category (we need to build electronic simulations of spiking neurons). 4. Quantum computers: they still cannot do anything but manipulate informat=on, but they can (hopefully one day) do a few things efficiently, like fac=oring large numbers, so they are in principle more powerful than conventio=al computers. thinks the universe is in this category, and thinks the brain is in this category. 5. Hypercomputers with true continuum dynamics. Such computers can solve th= 3 body problem with infinite precision in finite time etc. (Most of) trad=tional physics believed that the universe must be continuous, and even con=emporary physics usually has continuous time etc. Such computers can be ap=