I am reminded of how J.R.R. Tolkien’s mother once famously
corrected him at a very early age when he said ‘a green great dragon’.
She told him that it had to be ‘a great green dragon’, but when he asked
her why, she couldn’t answer, thereby starting him down the road of
puzzling over matters of philology (linguistics) his whole life long.
This topic is one of continuing research. Simply googling for
‘adjective ordering restrictions’ (AOR) or ‘adjective hierarchy’
can uncover some fascinating research in this area.
In her 2006 paper on “Adjective Ordering Restrictions
Revisited” on pp
309–407 of the Proceedings of the 25ᵗʰ West Coast Conference on
Formal Linguistics, Alexandra Teodorescu writes:
Adjective ordering restrictions (AOR) have been widely discussed,
but they are still not very well understood. For example, in
languages like English prenominal adjectives are strictly ordered.
…
For example, adjectives that denote quality have been argued to
precede adjectives conveying size, which in turn precede adjectives
conveying shape, and so on, in all languages (5). Similar claims have
been made for other adjective types, and the respective ordering
restrictions are given in (6).
(5) Quality > Size > Shape > Color > Provenance [Sproat and Shih (1991)]
(6) a. Possessive > Speaker-oriented > Subject-oriented >Manner/Thematic [Cinque (1994)]
b. Value > Dimension > Physical property > Speed > Human Propensity > Age > Color [Dixon (1982)]
See Teodorescu’s bibliography to chase down related work. You
should also look for papers that cite hers (Google Scholar finds 26 such
citations
to her work), like Lucas Champion’s 2006 paper on “A Game-Theoretic
Account of Adjective Ordering
Restrictions”, which
starts off with the Tolkien example.
Building then on Champion’s work is this English-language paper by
Antonia Androutsopoulou, Manuel Español-Echevarría, and Philippe
Prévost entitled “On the Acquisition of the Prenominal Placement
of Evaluative Adjectives in L2
Spanish”, from the 10ᵗʰ Hispanic Linguistics Symposium in 2008. This one is interesting
because it looks at how second-language learners acquire an
understanding of adjective ordering when learning a new language:
In this paper, we further investigate knowledge of adjectival
ordering restrictions in foreign language learning, by focusing on
L2 acquisition of evaluative adjectives (EAs) in Spanish by French
learners.
The most recent professional publication I could find on this issue
is Katy McKinney-Bock’s 2010 paper on “Adjective Classes and
Syntactic Ordering
Restrictions”,
in which she writes:
There is a lack of consensus in the literature as to which
classification of adjectives is directly relevant for the
observed syntactic restrictions on their ordering. In this paper, I
argue that adjectives are divided into four classes of relevance
for syntactic ordering. I propose that adjective ordering
restrictions (AOR) are the result of adjectival constituents
raising or not raising in the structure as a consequence of their
complexity, rather than stipulating that semantic properties
correlate to syntactic heads.
and whose extended abstract reads:
I argue there are four classes of adjectives relevant to
syntactic ordering: predicative/intersective,
predicative/non-intersective, non-predicative, classifying
(Svenonius 2008, Alexiadou et al 2007), and previous proposals
have not identified the relevant semantic dimensions. Among the
properties of gradability, mass/count, and intersectivity, only
intersectivity is syntactically relevant. The four classes of
adjectives are motivated by the distribution of
ordered/non-ordered adjectives, scope effects with certain
adjective-pairs, PP-modification, N-dropping and comparatives
(Bouchard 2002, Higginbotham 1985, Kennedy 1999). DP structure
involves 1) merging the classifying adjective with pronounced N, 2)
merging intersective adjectives with N, 3) merging
non-intersective adjectives with a silent copy of N.
Finally, if you’re looking for something slightly less professional
— or at least, less academic — then in this blog
posting,
the writer posits an ordering of:
- evaluation
- size
- shape
- condition
- human propensity
- age
- color
- origin
- material
- attributive noun
And summarizes with:
If there’s definitely a meaning difference between different
adjective orderings, let that determine how you order them, and
don’t use commas. If you can’t find a meaning difference, don’t go
trying to force there to be one. Instead, go by the
adjective-ordering hierarchy, and don’t use commas. If more than
one adjective has the same kind of meaning in the hierarchy, then use
commas, or ands or buts if the adjectives have contrastive meanings.
There’s a lot more out there on this topic.
"Light", as an adjective, can certainly mean having an abundance of light, i.e. not dark.
In your context, it is perfectly clear that you mean that turning on the lamp makes the room lighter. To that effect, the following is fine:
Having more windows, the kitchen was lighter than the living room.
Using the word "brighter" is more obvious without context because it doesn't carry the ambiguity of "lighter", that being that it can also mean "less heavy". Everyone knows that turning on a lamp doesn't reduce the weight of the room so, in your example, lighter works fine.
In summary, both are fine but if you think context is unclear then "brighter" would be more obvious.
Best Answer
Or is there really no grammatical rule to obey?
No, there is no rule, you can use any order you like:
"There were white, red, purple and pale-blue flowers on the table" is correct with any permutations of the colours