Let us move here the relevant discussion. (The moderator is kindly requested to move here anything that has hijacked the other thread, if he/she thinks that this is what has to be done.)
My point was this ; The single most important factor that determines if a knot A will slip more than a knot B ( or, if a knot A will slip, while a knot B will not), if they are tied on the same material, is the structure of the knot - and this structure is independent of the specific material those two knots are tied with/on. ( Of course, I mean “common” knot materials, that, even if they are more or less slippery, they are not springy, and can not be flattened very much, i.e. they retain a more or less circular cross section.) So, we can really say that a knot A slips more than a knot B, in general, because this relation is independent of the specific material, and can not be reversed if those knots are tied with/on whatever (“common”) material.
Based on this, I use very slippery materials - indeed, the most slippery I can find…- to test the security of knots, because, doing this, I can sometimes compare easily two knots that I can not compare when they are tied on a less slippery material ( because, there, it often is the case that no one will slip…) If I am lucky, the one knot will slip more than the other, and if I am very lucky, the one will slip while the other will not.
When I find that a knot A slips less, i.e. is more secure. than the knot B on some very slippery material, I am confident that the knot a will slip less than the knot on any other material, so I can claim that the knot A is more secure than the knot B, IN GENERAL. That does not mean that the material is something that can be ignored when we study physical knots ! Of course not ! I say that the specific material composition is neutral as regards this specific relation about two knots of a different structure, tied with/on a certain material the first time, and with/on another material, the second time.
I have not yet seen one single instance that this general “law” does not apply… so I dare to claim it is as general a “law” as it could be, indeed. I would be glad if somebody could point out to me a certain instance that is in contradiction to this general observation, which is a common experience to most knot tiers, I believe. I do not doubt that there could be some exception, and I am really eager to learn about it ! Iff we find some, or even one, such exception, we then, and only then, evaluate the situation again, and modify our view on the matter. If I see a giant pussy cat, revolving around the moon or the sun on their other side, then I will be afraid that I would be wrong - but this does not mean that I will not be allowed to have any claims, until we tie and try every possible knot, in every possible material ! Science, and scientific laws, are not generated by the absolute, exhaustive exclusion of every other possibility…Also, our claims have always a probabilistic sense ; I am sure that if I flip a fair coin 100 billion times, in about half of them the coin will fall on its one or its other side…but I can not exclude the rarest possibility that ALL those times, the coin will fall on the same side. And here we have not even discovered ONE SINGLE counter-example yet…
Somebody ties something with a rope and an overhand knot tied on this rope. The “knotted material” slips. A person A tells him : Try a different knot. A person B tells him : Try a different rope. A person C tells him : Use a metal fastener. A person D tells him : Use a glue.
Quiz : Who is the knot tyer ? 
P.S. I am not saying, of course, that a physical knot is not a knotted material ! I am saying that it is not only a material, which is knotted, and it is more than a knotted material. It is a knot knotted with/on a material. However, this thing has a structure that is (almost) independed of the material - as well as many other material-independed characteristics ( topology, geometry, etc.). And that the single most importand factor that determines if it slips more than another knot tied on the same material, is this structure. An overhand knot slips more than a fig. 8 knot, in ALL materials …so, in general, ceteris paribus, an overhand knot, as a knot, is less secure and safe than a fig. 8 knot.
Here I’ll copy a post --moved or not, it is here (at least).
(There are no apostrophes in X’s land of keystroke kraziness!)
Did you miss the point about knot ?
If one finds a material in which the thief knot works well,
what is the point to decrying its use there --perhaps by urging
further searching …-- where is suited?
[quote="Dan_Lehman post:25, topic:4307"]It’s not so simple. Nor is friction the sole determinant of behavior
–vs. flexibility, cross-section stability, & springyness, e.g..
[/quote]
That is why I said [i]“usual”/i, [i]“non elastic”/i material.
Hmmm, now X. becomes aware of material, though he seems
to want it only with “general” characteristics, not liable to unsettle
a structured perspective!
[quote="Dan_Lehman post:25, topic:4307"]And this conjecture about the inviolability of the significance of structure
is just that, and something I think I’ve seen hints of contradiction for.
[/quote]
Well, “I” have not ! And this is exactly what I have said, again and again, repeatedly :
… so much so as to ignore that I have pointed to one
case where security was reversed. Or that it seems to have
been (security vs. shaking loose), which is enough for me to
put doubt into such a broad generalization, knowing how
diverse knottable media is.
Xarax, you have gone gung-ho here (maybe “oauauao”, whatever
that new utterance is, too) over something that is conjecture on
your part, and not wise, in light of how diverse knottable media
is. Here is a simple case that I hope sheds some light on the
variability of security:
bowlines have been --and continue to be-- used for ages
in maritime use, without further precaution, for the most part;
their users laugh at suggestions that the knot will slip;
the knots can hold through to rupture, in testing;
but rockclimbers know to beware the bowline, because of
some well-publicized cases where it has slipped in the
sense of coming loose.
Now, I submit that if one put a shake test on a bowline
tied in some flexible, 12-strand HMPE (non-coated [and by this
I mean “not coated with urethane or other like treatment”,
and NOT “unsheathed” --but, yes, it IS unsheathed/pure]),
the knot will do better than one tied in springy slick PP, or
smooth-slick-&-firmish kernmantle;
BUT, put to the test machine (same knots exactly!),
the not-shaken-loose(now) latter knots (knots as knotted
material) will hold to break,
whereas that in HMPE will slip out, spill.
Yes, this is different than your Knot-A & Knot-B scenario;
but it shows the vagaries of knot behavior, and in has specific
aptness to the OP who wants security, entirely.
Please don’t read me as dismissing structure as important.
But we might come to --with improved, intelligent testing
and demonstration thereof of knot behavior across materials–
see some structures as preferable where materials are very
flexible, say, and other structures good in different cases
(and be less likely to try to find some universally best
structure).
–dl*
“material-dependent” <= correct form
Thank you, we are here.
(And I can think of another thread to follow.) 8)
My point was this ; The single most important factor that determines if a knot A will slip more than a knot B ( or, if a knot A will slip, while a knot B will not), if they are tied on the same material, is the structure of the knot - and this structure is independent of the specific material those two knots are tied with/on. ( Of course, I mean "common" knot materials, that, even if they are more or less slippery, they are not springy, and can not be flattened very much, i.e. they retain a more or less circular cross section.) So, we can really say that a knot A slips more than a knot B, in general, because this relation is independent of the specific material, and can not be reversed if those knots are tied with/on whatever ("common") material.
Note that “slips” is in your words, but I have in mind
some broader scope of behavior --i.e., staying tied under
jostling and low-tension working, as well as enduring some
strong force.
Based on this, I use very slippery materials - indeed, the most slippery I can find...- to test the security of knots, because, doing this, I can sometimes compare easily two knots that I can not compare when they are tied on a less slippery material ( because, there, it often is the case that no one will slip...) If I am lucky, the one knot will slip more than the other, and if I am very lucky, the one will slip while the other will not. When I find that a knot A slips less, i.e. is more secure. than the knot B on some very slippery material, I am confident that the knot a will slip less than the knot on any other material, so I can claim that the knot A is more secure than the knot B, [u]IN GENERAL[/u].
Allow me to suggest that “in general” is quite the
wrong assessment in such a case --where one has
found equality in most materials (in general !),
but only in some extreme (and maybe not so generally
extreme as one believes?) case is there a difference
(and maybe only with extreme forces).
I have not yet seen [u]one single instance[/u] that this general "law" does not apply...
Which is a valid point to note, but the challenge then
is to how broadly and well you have looked. Have you
seen the fisherman’s knot slip in kernmantle ropes,
e.g. --a surprise for me to learn, but Dave Richards’s
testing showed it to do so. Now, maybe you’ll reply
that you have seen it perform less well in some
slippery material (dental floss, I’ll bet!). My point here
thus is simply that we are not so well informed of the
behaviors of knotted materials (e.g., which of the two
asymmetric sides of a sheet bend “generally” breaks?
–after centuries, we might know this!?).
Science, and scientific laws, are not generated by the absolute, exhaustive exclusion of every other possibility...
But they need a firmer basis than you have so-far presented.
–dl*
Neither to Dan Lehman s stroke raze-ness !
The great knot tyer Dan Lehman solves all the knotting problems with/on one stroke ( guess where… :)). Find a material where ANY knot works well.
Well, I have to suggest a cure : Use Velcro, or chain ! So, we can forget anything age imposes on us, and be confident with the great knot, the overhand !
Thank you, materialistic wise man…You have corrected the idealistic fool, who thinks that things are ideas, made of thin quintessence…The world is not made by the shadows of things any more, but by the things themselves…
You have pointed out NOTHING. ( Not even a shadow of a thing !)
You have not “pointed out” which is the knot A and which is the knot B, and which are the two materials, with which the relation is reversed. And I think I know why, but I do not know any cure for this…
You confuse someone been wise, with someone who does not make conjectures…because he is so fool he is afraid his name will not be written with golden letters on the suit he will wear in the afterlife, if his conjecture will happen to be disproved some day. I might be wrong, but I have all the evidence you have not - and I am not a coward to be afraid of making conjectures ! You can not disproof this conjecture, so I guess it is wise for you to keep trying, not to try to portrait me as a fool…again. I am fed up with oracles- be brave enough to make YOUR conjectures, state them in the simple, clear way I dare to, and stop oauaouing about me being wise or not…
As a knot tyer, and a rational being which I hope you remain, that is an (evidently) true statement. As a lawyer, you should nt finish your speech with this !
Yes, true, we might come to such a conclusion - but we are not already there, are we ? Until then, I do not fear to suggest a conjecture, based on much experimental evidence, rational examination and common sense ! I am not afraid that there is a possibility that my conjecture will be falsified… On the contrary, I will be glad if that happens, and i pray it will happens during my short lifetime… ! That is how science proceeds, my dear Dan Lehman, not in the courts of (forums) law, not in the world of key or brain strokes, but in the real world of Nature. Till then, I will continue to try to find the best structure, the most secure and safe knot, and I suggest you do so, too - and you leave Velcro and chain to others.
P.S. Do not come again in the issue of flexible (elastic) material…I have said many times, again and again, that with materials that are elastic or easy flattened, it would be too easy to find exceptions to “my conjecture”.
That is exactly why we should resolve the reasonable question “which knot slips less, is more secure and safe, in general”, by going to the limit, to extremes, as it often happens in science. The truth reveals itself only there, but that does not mean it is not present elsewhere…And we should resolve the question indirectly, through analogy - and then be bold enough to conjecture that the relation we have found remains valid throughout the whole scale.
We can not test most of the knots we use about which is more secure, in general, because, in general, all those knots will not slip with most of the materials we now use. But what will happen tomorrow, for example, if we start to use spectra/dyneema, or even graphene ? And what will happen if our material got wet, with water or oil ?
I believe that, as structure is an invariable, and slippage depends mostly upon structure, it will also be an invariable quantity. And that makes me think we can test this quantity by going to the extreme cases, with extremely slippery materials, and extremely strong forces, and then guess that what we find will remain true - even if it is hidden from us - and it will not be reversed through out the whole scale of materials and forces. Nature is subbtle, but it is not malicious !
True, and it might turn out that this fool will teach you something in this case, this century - if my amateur universal testing machine solves the problem of noise, which disturbs my apartment neighbors :)…
You are wrong ! Science has often been forced to rely in much less evidence than we have in this case…because scientists, based upon their imagination and experimental “feeling”, judging by analogy and extrapolations, were bold and brave enough to generalize and propose conjectures with few only evidence.