it was best not considered

Question

Clash of Kings by George R. R. Martin

Soon they were high enough so that looking down was best not considered. There was nothing below but yawning blackness, nothing above but moon and stars.

The author meant that you shouldn't have looked down because of this white-knuckle height. I understand that this can be paraphrased: it was best not to consider it

But what is the grammar behind this structure? I've found that there is a structure "(had) best do something". You can use it in the past like in this example: You had best have closed that door. But I couldn't find the phrase used in the book (was best not considered).

When thinking on it some time, I came up with some more phrases which are similar to the one in the book:

1.It was best not to be considered
2.It was best not to consider it

The 2nd variant sounds natural to me. The first seems wrong because to be considered means some obligation. (You must not look down!)

But what about the variant in the book? Can anyone explain it to me in terms of grammar?

Thanks in advance

Answer 1

1a It was best {not considered}. It was = pronoun + to be; best (adjective);{Not = adverb; considered = adjective} = unconsidered = adjective.

1b. It was best not to be considered – to be considered = pronoun + passive infinitive. The implied agent is “by you/him/one, etc”.

2. It was best [for you/him/one, etc] not to consider it – to consider is the active infinitive. [For you, etc.] is an adverbial modifier = “in your case”, and modifies “best”

Compare “It was best {not considered}” with

The porridge was best hot

The porridge was best (adjective) {[when it was] hot [porridge].} adverbial clause modifying "best".

Answer 2

The examples in the question are using "best" with forms of the verb "consider", while Martin is using [considered] / [not considered] as an adjective.

From Kate's comment, "You had best close that door" refers to the verb - to the action of closing it.

If we wanted to refer to an adjective, we could say "That door is best closed", or borrowing Martin's style and tense, "That door was best [not open]".