studiot

As a furniture crafter I think you will understand the different between a pattern and a model. A pattern is something we use when we already know all we need to know about something we want to make either as a one off or many times over. A model is a copy of something that either already exists or we want to make or study. But it is never a perfect copy. Otherwise it would be exactly the same as the object etc under consideration. The model will be as close a match to the features or characteristics as we can manage, but may well be quite different in characteristics we are not interested in. For instance we may make a model aircraft to test in a wind tunnel. It will probably not be the same colour, may not be the same material, will almost certainly not have any 'interior' not be the same size etc. But it will have the same aerodynamic characteristics as the proposed aircraft. Because we hope it will fly in the same way. Sometimes we simply want the mathematics to be the same and we call this a mathematical model. Here is probably the most widely used mathematical model of all. The curve is the same whether we are talking about radioactivity, some electrical circuits, first order chemical reactions, population decline, drug elimination from the body, a sound dying away in a concert hall and many many more. How are we doing ?

I can't see why you think I had a dig at anybody. To quote your AI Let me be blunt I told you exactly what I thought lay behind you communication difficulty, (aka chasing the wrong rabbit) and offered an insight - that you should find out exactly what Science (all science and maths has the same definition) mean by a model. And you ignored it, instead choosing to ask an AI rather than a human. As a matter of interest would you give apprentices sharp chisels, saws, planes etc and just let them loose ? Or would you start by making sure they know how to safely handle these tools, then set them to go on and fashion furniture you (or others) have not dreamed of ? Quite a few members here are quite pround of the amateur woodwork, but would be glad to learn tips from a professional. There are several threads with photos etc about this.

You have no way of knowing how i learned my stuff, so you are making unjustified assumptions, and I didn't say anything about going to uni. For your information we have one or two self taught members who are regarded as expert in higher Physics and its associated maths. Everybody take note of their always excellent posts.

Yes indeed. Perhaps because you have been teaching yourself for so long you don't like to learn anything form anybody else ? In this case I suspect you don't understand the nature of models in Science generally. ? As a result you are chasing the wrong rabbit.

I didn't say or mean it was a 'metric'. My question stands regardless.

There are several ways. The forum editor allows you to to do some very simple but very useful things like superscript and subscript directly, and is the only tech forum I Know that does this. Click on the three dots at the right hand end of the top bar. You can enhance that by using the extended character set to select other simple maths symbols, greek letters and the like. Just open (by typinginto the search bar) the Windows tool 'Charmap.exe' Then select the symbols you want and copy/paste them inot the text. It can be more efficient to have two or three selected and delete the ones you don't want from the pasting. All this only gives in line maths. So if you want fractions or more complicated expressions, As KJW is showing., we use LaTex or MathML. There are a couple of free online editors. Just assemble the expressions, then copy and paste from the editor to SF. I use a commercial version called MathType. https://www.sciweavers.org/free-online-latex-equation-editor https://editor.codecogs.com/ Actually you can construct Pi geometrically, without a circle. Draw a line about 5 units long. You have constructed all the number between ~0 and ~5 This must include Pi as it is such a number. But it is impossible to draw a line of exactly Pi units length with standard construction techniques.

Well it sounds like you have progressed a long way forwards if you can recognise all this in yourself. +1

I never said they did so exist. But I don't understand what yo umean by nonmaterial abstractions. If you mean that abstractions, whatever they are , don't exist then I would challenge you to go and stand for half an hour in the middle of the road outside my house at noon. The walk over to the verge and stand under one of the many trees. Then tell me that there is no such thing as a shadow or that the non material cannot affect the material world or somesuch. That is how I am understanding/interpreting your words.

Thank you for exploring this further. +1 This question is far from fully worked out so 20th century studies have revealed that the 19th cent pat heirarchy of integers, rationals, reals, complex, etc. Yes louiville's theorem is important but the new stuff was ushered in by Hensel and his p-adics., leading to the notion of other number fields that are different from the reals @mike.appleby It might be worth exploring the mathematical question of what is a number a bit further and selecting a suitable understanding for your purposes. Understanding that sequence ( integers, rationals, reals, complex, etc.) is enough for your purposes. Suffice it to say the 'Pi ' is a real number, nothing special at all. As such it appears in many ways in mathematics, in geometry, calculus, trigonometry etc, just like any other number. But note I mentioned coefficients before. Coefficients are more general than numbers in that are modifiers, but they can refer to other things than quantity. Numbers are the usual ( but not exclusive) quantifiers. Numbers are quantifiers of properties that can carry units or dimensions. Young's modulus for example carries units. But other properties such as refractive index do not. Nevertheless they still need quantifying. But there are also different types of number. And these different types obey different rules of arithmetic. For example adding first and fifteenth make no sense at all. Such numbers are called Ordinal Numbers nad carry no meaning of quantity. Numbers that convey quantity are called Cardinal Numbers. Remember also that, for instance π is a symbol or representation of the number itself: It is not the nember. I called it poetically ironic because Buckinghams π theorem is named after the mathematicians use of the capital Pi to represent multiplication in the same way capital sigma is used to represent addition. So as (nearly) always it is more complicated than we might like.

I find it poetically ironic that of all the numbers on the number line, you find the one that has a special place in dimension theory to argue with (believe something different about). FYI dimension theory in Physics (which is quite different from the much more difficult dimension theory in Mathematics) was originally expounded by a man named Buckingham. And there is a theorem named after him. Buckinghams Pi theorem. https://en.wikipedia.org/wiki/Buckingham_%CF%80_theorem Note the use of the word dimensionless.

Beware also that ML2T-2 represents other quantites than just energy.

I agree there is a serious ethical dilemma. +1 Not just for thos edirectly involved but also for those who employ them or are in charge of them. Compare this situation with prison warders and prison governors and the prisoners themselves. Very similar ethical dilemmas exist here too. And how about soldiers with PTSD ? This whole thing runs wider in our society.

One thing you need to be careful of are electrical units and dimensions, because in some systems dimensionless constants exist, that are absent in others. Look up esu and emu units.

Thanks so the issue is much wider than just the patient. How does society ensure that the 'right' sort of person or persons makes the decision ? How far should the patient's wishes be considered ? If the patient's wishes are to be overridden, who will be there to see that the aptient's interests are served ?

Well at least you are prepared to consider the possibility of being to hasty. What do you know about units, dimension theory, and coefficients in maths and physics and the difference between them ? One thing is that different sets of both base units and/or base dimensions may be chosen which will make the actual values different.

I also asked what is your connection to this issue ? and About the doctor who would have to implement your scheme. Both of these had question marks at the end and have not been answered. In respect of that second question about the doctor, I have in mind a couple of incidents I know of. In one a doctor had to climb onto the steelwork of the Severn Bridge and cut off a limb from a trapped worker in order to free him. How do you think that doctor felt about that ? Secondly someone I was close to underwent compulsory ECT. Again it 'worked', but destroyed their creativity and turned them into a shell. Nor were the effects permanent. So let us discuss the ethics of such actions and the effects. not only on the patient but also the doctor(s).

So what about Reynolds Number ? I chose this one because it is probably the one most likely for you to have heard of, but there are plenty more. You can't get more physical than the ratio of inertial forces to viscous forces which determines the flow regime.

Perhaps you should review your command of the English language. You can usually tell a question by the inquiring phraseology/tone of the words and the question mark at the end. Alternatively the questioner can phrase the question more politely. So please don't tell me that I haven't asked any questions in my own language.

So are we agreed that your train of thought was incorrect in stating that it requires Pi to have units ?

What about this phrase of mine leads to you think that I assumed anything at all ? And you still haven't answered my questions.

Please explain this apparantly unconnected response and answer my questions.

Let me ask you this simple question. What proof or evidence do you have to back this claim up ? I ask because your use of 'it must' and 'thus' means that you consider there is some Law that requires this. So please outline this Law. I observe that any worthy summary of Physics will contain a section on 'dimensionless constants' , such as Reynolds Number, which have no units but definitely affect that which they are applied to, in defiance of any requirement to the contrary.

How is that an answer to my comments ? What I do not understand is you connection to this issue or why you have abandoned answering in your previous thread ? I wonder if you have any idea at all of what a doctor goes through when treating a patient necessitates damaging them in some way ?

I asked you a very clear and simple question, in the hope that you would gain something from it. But you did not answer, instead choosing to hide any response in a flood of meaningless text. I will now ask another one. What is the difference between circular language and ontologically circular language ?

Oh. And there was I thinking that it would cause chicken little a great headache if it fell. 😄