Page 1 of 1

Real-life Turing machine

Posted: March 19th, 2021, 9:20 am
by {censored}
Would it be easy? Would it be any similar to Conway's one?From what it would be made?I think few ever were thinking about this so I made a thread.

Re: Real-life Turing machine

Posted: March 19th, 2021, 9:35 am
by dvgrn
{censored} wrote:
March 19th, 2021, 9:20 am
Would it be easy? Would it be any similar to Conway's one?From what it would be made?I think few ever were thinking about this so I made a thread.
Do you mean a real-life Turing machine -- which is technically impossible since one of the specs is an infinite data tape -- or a real-life self-replicator?

Self-replicating machines seem like a technological advance that's so huge it will change everything -- so much so that I'm surprised Elon Musk hasn't started a company to research them yet. As far as I know. I suppose we really shouldn't be expecting Elon Musk to do all of the crazy research and company-building, though -- he's already pretty busy.

Re: Real-life Turing machine

Posted: March 19th, 2021, 9:55 am
by {censored}
Yes,moderator.
So completely impossible?I heard some games are Turing-Complete. What that means?
Those machines would need to eat....

Re: Real-life Turing machine

Posted: March 19th, 2021, 10:06 am
by Schiaparelliorbust
{censored} wrote:
March 19th, 2021, 9:55 am
Yes,moderator.
So completely impossible?I heard some games are Turing-Complete. What that means?
Those machines would need to eat....
Games like Minecraft are said to be Turing-complete because if run on an ideal computer (Turing machine), you can make a Turing machine in them. By "game" do you mean CA rules though?

Re: Real-life Turing machine

Posted: March 19th, 2021, 10:09 am
by {censored}
Schiaparelliorbust wrote:
March 19th, 2021, 10:06 am
{censored} wrote:
March 19th, 2021, 9:55 am
Yes,moderator.
So completely impossible?I heard some games are Turing-Complete. What that means?
Those machines would need to eat....
Games like Minecraft are said to be Turing-complete because if run on an ideal computer (Turing machine), you can make a Turing machine in them. By "game" do you mean CA rules though?
No,but about computer ones and Magic:The Gathering,a card game.

Re: Real-life Turing machine

Posted: March 19th, 2021, 10:20 am
by Moosey
{censored} wrote:
March 19th, 2021, 9:55 am
So completely impossible?
In reality there are physical limitations on how much data can be stored. Though the amount of data that can be stored is very large, you can't really make it infinite due to said limitations. Therefore, a true turing machine with infinite data storage would be impossible irl. However, if you're ok dropping the requirement for infinite data storage, then these would meet the criteria.
{censored} wrote:
March 19th, 2021, 10:09 am
No,but about computer ones and Magic:The Gathering,a card game.
ah yes, the turing completeness proof of MTG

Lots of games have crazy weird mechanisms for turing completeness. See also: infinite minesweeper.

Re: Real-life Turing machine

Posted: March 19th, 2021, 2:06 pm
by {censored}
What about partial ones,with the finite tape?

Re: Real-life Turing machine

Posted: March 19th, 2021, 2:36 pm
by dvgrn
{censored} wrote:
March 19th, 2021, 2:06 pm
What about partial ones,with the finite tape?
They've certainly been built, for some definitions of "finite tape" -- see TOWTMTEWP for example, there's a Youtube video about it.

Not sure if anyone has ever built one with an actual paper tape -- a row of on/off switches is so much simpler to implement!

Definitely not a lot of candidate Real Life Turing machines have ever been built, because when you come right down to it they're painfully inefficient at calculating anything.

Re: Real-life Turing machine

Posted: March 19th, 2021, 2:46 pm
by Macbi

Re: Real-life Turing machine

Posted: March 19th, 2021, 3:05 pm
by {censored}
Are they any similar to those in cellular automata?
They would need to eat in order to reproduce. Any ideas about how that could be done?

Re: Real-life Turing machine

Posted: March 19th, 2021, 3:21 pm
by dvgrn
{censored} wrote:
March 19th, 2021, 3:05 pm
Are they any similar to those in cellular automata?
They would need to eat in order to reproduce. Any ideas about how that could be done?
First answer the question I posted in response to your first post:
dvgrn wrote:
March 19th, 2021, 9:35 am
Do you mean a real-life Turing machine -- which is technically impossible since one of the specs is an infinite data tape -- or a real-life self-replicator?
There's nothing in the definition of a Turing machine that says anything about them reproducing, let alone eating. They're mostly just mathematical models of computation -- nothing to do with self-construction at all.

You seem to be thinking of self-replicating machines, von Neumann probes, or something along those lines. That's a very different question, with very different answers.

Re: Real-life Turing machine

Posted: March 19th, 2021, 3:32 pm
by {censored}
By definition Turing machines can compute anything, including them,yes?

Re: Real-life Turing machine

Posted: March 19th, 2021, 3:57 pm
by dvgrn
{censored} wrote:
March 19th, 2021, 3:32 pm
By definition Turing machines can compute anything, including them,yes?
A Turing machine could "compute" the behavior of a self-replicating machine, at various levels of detail... sure, I guess. But that would be a simulation of a self-replicating machine -- there isn't really anything "real-life" about that scenario.

Re: Real-life Turing machine

Posted: March 19th, 2021, 4:45 pm
by {censored}
Yes, that is surely not going to happen, or at least not soon.
Who knows,maybe we will one day discover a Turing machine with a finite tape!Who knows what future holds.

Re: Real-life Turing machine

Posted: March 19th, 2021, 5:37 pm
by dvgrn
{censored} wrote:
March 19th, 2021, 4:45 pm
Yes, that is surely not going to happen, or at least not soon.
Who knows,maybe we will one day discover a Turing machine with a finite tape!Who knows what future holds.
Heh, we know a few things that the future doesn't hold, and that's one of them. The definition of "Turing machine" specifies an unbounded tape, so if you have a finite tape, it's not a Turing machine.

It's not just a matter of definition, though. A finite tape means the "Non-Turing-Machine" has a specific limit to the amount of information it can store. Then it becomes really trivial to give an example of a problem that a Turing machine can solve, but the Non-Turing-Machine can't solve -- it's provably a much less powerful model of computation.

Re: Real-life Turing machine

Posted: March 20th, 2021, 8:06 am
by {censored}
Not nesecarrily if there is magic. We do not know yet.

Re: Real-life Turing machine

Posted: March 20th, 2021, 2:14 pm
by Moosey
I think $$\nexists magic$$ is a reasonable assumption

Re: Real-life Turing machine

Posted: March 26th, 2021, 7:16 am
by Hunting
{censored} wrote:
March 20th, 2021, 8:06 am
Not nesecarrily if there is magic. We do not know yet.
Or quantun mechanics perhaps? Although I don't know quantum mechanics at all.

Re: Real-life Turing machine

Posted: March 26th, 2021, 7:59 am
by Schiaparelliorbust
Hunting wrote:
March 26th, 2021, 7:16 am
Or quantun mechanics perhaps? Although I don't know quantum mechanics at all.
I'm pretty sure there was some proof last year about quantum mechanics and Gödel's Incompleteness Theorem, but I can't find it right now. I'll keep looking for it.

Re: Real-life Turing machine

Posted: March 27th, 2021, 12:18 am
by pcallahan
dvgrn wrote:
March 19th, 2021, 9:35 am
{censored} wrote:
March 19th, 2021, 9:20 am
Would it be easy? Would it be any similar to Conway's one?From what it would be made?I think few ever were thinking about this so I made a thread.
Do you mean a real-life Turing machine -- which is technically impossible since one of the specs is an infinite data tape
Well, you can keep increasing the storage as needed. There is almost certainly enough time as long as you start with enough runway. On nontrivial computations, the head may spend a long time in the interior, giving you time to add to the frontier. Of course, you eventually run out of material to make new tape, but depending on the speed, the universe might end first.

I would have interpreted this question not in terms of infinite storage but in terms of the read/write architecture of only making changes on a tape cell and moving sequentially left or right. That is probably not the questioner's intent though, either. You could certainly build a real-life machine with this kind of access, though it's not very interesting.

Maybe there is something that would work along these lines at the molecular level, making changes back and forth along a polymer chain, though that is probably pure fantasy. However, that or else a literal, mechanical implementation are the two things that come to my mind when I hear "real-life Turing machine".