On 11.03.2022 13:22, Klaus Kassner wrote:
> Am 10.03.2022 um 07:23 schrieb Janis Papanagnou:
>>
>> Why are you assuming that? If you know the underlying algorithms you
>> can simply determine it. And if you don't know the algorithm (by Wiki,
>> source code, or whatever) you can do the experiment on the fly; "step,
>> step, step, one-quare-space-gained" - remember? It suffices that you
>> know that there's no RNG involved and the experiment will provide you
>> the actual deltas. That's also what I do; I'm not doing calculations,
>> I am testing the delta once and apply it subsequently, and I do that
>> _in practice_.
>
> I already agreed that this works for unburdened, but I still do not´know
> that it is that simple for burdened. At one point, you seemed to say
> that it depends on the degree of burden (by which I thought an internal
> number depending on the actual overweight, not just on the three degrees
> burdened, stressed, strained).

Have a look at the Wiki (https://nethackwiki.com/wiki/Speed) for that.

> Since I do not know the algorithm, I
> cannot do the calculations, which makes it random for me, [...]

It's hard to get rid of the idea that a calculation would be necessary?

> In practice, you simply
> may not have the time to determine this when needed.

This is indeed true for tight situations (getting surrounded, standing
with your back at the wall, etc.).

Where I apply it are the more common standard situations that you have
a route to escape, so you can make a few steps to check that "delta"
and then make use of the free turn.

>>> But there is randomness in the standard sense: sufficiently chaotic
>>> dynamics, and lack of knowledge to determine a unique outcome.
>>
>> But that isn't the case here with the movement-scales. - Why do you
>> think it is?
>
> Because I do not know of a simple algorithm for the case of burdened,
> stressed, etc.

The focus on the "algorithm" might make the simple solution appear to
be more difficult than it actually is.

> In the case of unburdened I agree that it is not random, [...]

There's no algorithmic difference between unburden and burden here;
it's just another scaling factor. But the concrete factors are only
necessary for the algorithmic computation, not for the tests on the
fly that I had described, where it is irrelevant whether your speed
has internally a value of 16 or 12; you just observe and count steps.

> once I take the care of observing the sequence of two and one moves --
> because that sequence is repetitive enough for a human brain to make the
> prediction. If the sequence has a period of, say, 20 steps, I may
> already need paper and pencil to ascertain the periodicity. [...]

It is not that bad; one typically needs to count only up to 4 or 5.

>
>> Whether other functions - off-topic here! - are truly random or not I
>> cannot tell. It could be that the various random functions in Nethack
>> rely on a PRNG algorithm, or it could rely on an RNG provided by the
>> operating system. In the latter case that could be retrieved from a
>> device that either relies on an OS-library algorithm that actually is
>> again a PRNG, or it can rely on some quantum effects of HW-circuits.
>>
>> Here, for example, is a quote from my OS'es description, obtained by
>> the command 'man urandom':
>>
>> random, urandom - kernel random number source devices
>> ...
>> The random number generator gathers environmental noise from
>> device drivers and other sources into an entropy pool. The
>> generator also keeps an estimate of the number of bits of noise
>> in the entropy pool. From this entropy pool random numbers are
>> created.
>
> A PRNG would be deterministic, of course, having a finite period.
>
> Any RNG that does not use the random effects of quantum mechanics in
> some way would be deterministic, not necessarily by having a periodicity
> that could be determined, but by its random numbers being predictable by
> an appropriate computer program that gets all the input data of the RNG.

The point is (IMO) that whenever you use external physical sources you
often can't really tell. (Even if we make a philosophical difference
between randomness of chaotic systems vs. quantum mechanic randomness.)

Say, you use the urandom device mentioned above, the "noise" stems from
a hardware device, the noise is affected by eg. temperature, radiation,
etc., - while you may argue that temperature is just a chaotic but not
a quantum effect, which I doubt since it's also influenced eg. by solar
activity - the radiation is affected by solar wind particles, the
particles are from nuclear fusion processes, these processes are based
on QM-effects.

> (More simply, take a second RNG of the same kind, make sure it receives
> the precisely same input and starts with the same internal state, then
> it will give you the same sequence of random numbers. If you run the
> second RNG in a way that gives you the random nubers a minute earlier
> than those of the first, then you can predict the latter with certainty
> a minute ahead of time. So they are clearly deterministic.)

For that definition we would (IMO) need no quantum effects to support
non-deterministic behavior. The problem I see with this view is that
it assumes an "internal state". While in the simple case of a PRNG we
clearly have such a state (unless it is seeded non-deterministically),
but using any external source it just depends, we cannot tell.

>
>> And we disagree in that it has any relevance in the given
>> case, where there's no dispute necessary what randomness actually is,
>> because there isn't any (neither a PRNG, nor an "unknown mechnics" RNG,
>> nor a RNG based on quantum mechanics effects), in the given case.
>
> Yes, there we disagree, because you can have randomness without an RNG.
> The algorithm acts as an RNG, if your knowledge is sufficiently restricted.

I think the point to get confidence is not the knowledge of algorithm
(which seems to imply again the mental model of players calculating
the effects based on probabilities), but knowing that what we want to
know can be simply observed by usually possible ad hoc tests together
with the meta-knowledge about the algorithm that it's deterministic.

>
>>> So if you accept only "true" randomness as
>>> random, then saying there is no randomness here is an empty statement,
>>> because there is *never* randomness (as we excluded quantum mechanics).
>>
>> I didn't exclude it.
>
> Yes, in saying that it is irrelevant here. If it is irrelevant, it can
> be excluded from the discussion.

Yes, for NH-343 (where the algorithm is deterministic) we can exclude
it, but for NH-36x case (where the algorithm is influenced by a PRNG)
we cannot exclude it. And with the reference to the external physical
"noise" effect based mention of the urandom device I have explicitly
not excluded it.

> I am less knowledgeable here than you. I simply assumed that NH uses a
> PRNG [...]

This is true. (I have described details just recently in a reply to
Isidore.)

>
>>> But if you take the point of view of physics that randomness in practice
>>> comes from lack of knowledge, then of course there is randomness -- for
>>> the player -- in the way the number of moves per turn is determined,
>>> even in NH3.4x.
>>
>> So for someone who has inspected the source code or informed himself
>> from the Wiki it's non-random and for others, uninformed folks, it's
>> random?
>
> Yes. Randomness is not absolute.

My question was whether you consider randomness is a subjective term
based on the information grade of the subject.

Whenever we can show a causal deterministic relation you can't say it
is random just because any subject isn't aware of that. A subjective
definition is of no [general] use, it makes no sense for a normative
defined term.

>
>> - If that's what you are saying then this definition makes no
>> sense to me; it's certainly of no use here.
>
> So you are saying it is useless that throwing dice gives you a sequence

No, I was saying what I repeated above.

> of random numbers, even though each single result could be predicted by
> a physicist with an appropriately sophisticated experimental apparatus,
> [...]

As there's enough money to make with such an apparatus, and since no
one did so far, I'm continuing to look James Bond films to see such
devices and listen to physicists talking about the possibility. :-)

>
>> We spoke about the profane topic whether we can determine the free turns
>> or not - yes, we can! -, and whether the algorithm is deterministic or
>> not - yes, it is!
>
> No. We were talking about whether there is randomness involved,
> requiring a probabilistic description, and that does not depend solely
> on whether the algorithm is deterministic. If it is not, we surely have
> randomness, but if it is, randomness depends on the knowledge state of
> the person/entity dealing with the problem. [...]

The encyclopedias seems to disagree with you.

>
>>> To state it succinctly, randomness is in the eye of the beholder. Except
>>> in quantum mechanics.
>>
>> Fine. Here, with this statement, we have finally reached agreement. :-)
>
> Strange. Because if randomness is in the eye of the beholder, then it
> may clearly be present also in deterministic systems.

Wrong conclusion. If subjective randomness is in the eye of the beholder
then the beholder doesn't know of any rational deterministic cause that
would explain this presumed random behavior. The subjective thinking of
any person has absolutely no effect on the deterministic system, which
is certainly deterministic independent of any subjects.

Okay, enough for this thread. Let's agree to disagree.

Janis
--
Von Zufall spricht man, wenn für ein einzelnes Ereignis oder das
Zusammentreffen mehrerer Ereignisse keine kausale Erklärung gefunden
werden kann. Als kausale Erklärungen für Ereignisse kommen je nach
Kontext [...] auch naturwissenschaftliche deterministische Abläufe in
Frage.