What is the Meaning of First Principle in Chemistry?

[sandf]

TL;DR

What is the difference among the expression of "first principle, first principles, first-principles, and first-principle calculaltion"

Dear all,
I am sorry if the topic is not appropriate in this subForum.
As a chemist, I am confused by the expression of "first principle, first principles, first-principles, and first-principle calculaltion".
In chemistry, we only use "ab-initio".

Best regards.
Youzhao Lan
Department of Chemistry,College of Chemistry and Life Sciences,
Zhejiang Normal University,
Jinhua, Zhejiang,
321004, China.

 

[sysprog]

You could also use 'ex ante' or 'a priori' or 'de primis principiis' $-$ they all have similar meanings $-$ the differences are apt to be of primarily merely stylistic import.

 

[sophiecentaur]

merely stylistic import

This can be a problem. Using terms that are way above the basic level of a technical discussion can be seen as a 'weapon' to establish the correctness of an argument. There's probably an equally posh term for that kind of thing. ;-)

I would say that the term 'ad initio' should be used amongst people who also use and recognise it. The way you read "first principle" should perhaps be based on context where it's used. This English language can be a minefield and can carry all sorts of hidden messages which may or may not have been put there deliberately. Many technical discussions can most safely be interpreted using the Maths rather than the linking comments.

 

[sysprog]

Many technical discussions can most safely be interpreted using the Maths rather than the linking comments.

That's especially true in the case of LaPlace, who was won't to employ such discursive devices as (roughly translated from the French) "wherefore it can easily be seen that", for things that he just couldn't be bothered to prove.

 

[sophiecentaur]

That's especially true in the case of LaPlace,

And what about Fermat? He never actually provided a proof of the bombshell he left us with. It was left unproven for a long while, until Andrew Wiles sorted it out twice, 358 years later. A very cheeky 'conjecture' I reckon.

 

[sysprog]

And what about Fermat? He never actually provided a proof of the bombshell he left us with. It was left unproven for a long while, until Andrew Wiles sorted it out twice, 358 years later. A very cheeky 'conjecture' I reckon.

I have a suspicion that Fermat envisioned drawing a graph with a z axis, and showing that while satisfactory triplets were findable in the plane, none that had a non-zero z value could be found in the cube $-$ that would account for his remark that his proof wouldn't fit in the margin $-$ if it was along such lines, it presumably wasn't really a proof $-$ but also presumable is that Fermat would likely have had something more than mere absence of disproving evidence before he would suppose that he had a proof.

 

[Mark44]

This can be a problem. Using terms that are way above the basic level of a technical discussion can be seen as a 'weapon' to establish the correctness of an argument. There's probably an equally posh term for that kind of thing. ;-)

An instructor I had for a college calculus class used to say, "obvious to the most casual observer" or "even my own mother could integrate this."

 

[sophiecentaur]

That was fresh for you but, over the years, every poor student got the same smart remark dished up every time. Just like comedians in the old music halls.

 

[Bonkers]

to the Original Poster, OP,
the terms are identical in meaning, any form of words mentioning First Principle(s), will be talking about the same thing.
Often, First Principles are used to describe a simple understanding, and an expectation - only then to contradict it with the reality.
Chemistry has many such instances, as I'm sure you will know.

The Laws of Chemistry are, as we say in England, amongst physicists, "More honoured in the breach than the observance"

In return, Physicist's simplifications are often referred to as "Spherical Cow" type arguments. I leave you to look that one up..