Is it just me or is 却向人类早已认定为准则的定义提出了质疑 terribly unnatural?

Question

俗话说万物生长靠太阳。人们之所以这样说，是因为历来植物生长离不开阳光，而动物又靠植物维持生命，所以没有阳光，就没有万物，这是众所周知的真理。然而科学家们的深海考察，却向人类早已认定为准则的定义提出了质疑。
_{HSK Standard Course 6上, chapter 19 (original).}

This is the first paragraph from a chapter in the HSK Standard Course 6上 textbook, which discusses deep sea life and how it survives without sunlight. The last sentence above seems very weird to me.

To begin with, the choice of the word

CC-CEDICT: 准则 (zhǔn​zé​) norm / standard / criterion

seems mismatched with both the scientific context (wherein 原则 or 原理 would be more appropriate) and with the use of 认定 (instead of, say, 公认).

The second problem I see is the use of

CC-CEDICT: 定义 (dìng​yì​) definition / to define

It's not clear (to me, at least) what definition(s) the passage is referring to. I feel like it's referring to the prior-mentioned 真理, i.e. 没有阳光，就没有万物, but this is not a 定义. Moreover, the use of the word

CC-CEDICT: 质疑 (zhì​yí​) to call into question / to question (truth or validity)

seems inappropriate (to me) for describing 定义. Furthermore, the text makes it sound like scientists are making an important discovery, and not merely that some 定义 is inappropriate and needs modification.

I might be completely wrong about all this. However, in a previous chapter from this textbook, I compared the textbook's text with the original (unmodified) text, and the textbook "forces in" certain vocabulary items, and the result is unnatural.

Question: Is it just me or is 却向人类早已认定为准则的定义提出了质疑 terribly unnatural?

If it helps, Chinese Zero to Hero breaks apart this part thusly:

……却向（人类早已认定为准则的定义）提出了质疑
...have raised doubts about (this definition which humans established as a truism a long time ago).
_{Chinese Zero to Hero (screenshot)}

Answer 1

Here is my takes:

"历来植物生长离不开阳光，而动物又靠植物维持生命，所以没有阳光，就没有万物" - 真理 (a tested rule that is considered the truth).

"万物生长靠太阳" - 定义 (a definition).

The sunlight maintaining and extend the life of creatures is considered the "norm"; the creatures can't live without sunlight is the "standard phenomenon" and the sunlight is the "criterion" for maintaining and extending lives. Thus it is a "准则" as defined by 万物生长靠太阳.

原则 and 原理 are not suitable for this case as:

"原则" has the meaning of "basically" and "a bottom line cannot be violated".

• Basically, creatures need sunlight to maintain life. (原则上, 生物需要陽光維持生命)

• This is the bottom line that cannot be violated. (這個原则是不能違反的)

"原理" is a "theory", which is a basic generalization that is accepted as true and that can be used as a basis for reasoning or conduct, or a generalized rule or law concerning a natural phenomenon or the function of a complex system.

By the way, seems this paragraph is an excerption from a scientific paper, I suggest checking the terms - 定义, 原理, 法則 from a more technical source such as a textbook for physics, rather than the regular dictionaries, which tend to offer overly broad explanations to suit varies areas but the precise meaning in the respective science field.