Language discovery

[sister_luck]

Words follow rules that are sometimes rather mysterious. Today I found the following sentence in one of my students' essays:

[*]This amount isn't possible to eat and isn't possible to produce.

Nevermind what this is about, but I bet you'll agree with me that this sentence is not well-formed.

A small change does the trick though:

This amount is impossible to eat and impossible to produce.

That's kind of weird, isn't it?

My trusty Practical English Grammar doesn't tell my why, but notes that while convenient, dangerous, difficult, easy, hard, impossible, safe, unsafe can be used in the noun + be + adjective + infinitive construction, possible is an exception. Their examples are

This cake is easy to make.
The instructions were hard to follow.
The car isn't safe to drive.

and replacing these adjectives with possible just leads to confusion.

Is it just a question of logic? Is there a reason for this phenomenon? Or is it just a mystery?

Comments

[frances-lievens.livejournal.com]

The thing is that you can actualy say: "That's not possible." But you don't say "It's not possible to..."
I think I'd make the same mistake, but I do understand the reasoning and hear that using impossible with an infinitive is the correct one.
Maybe possible can only be used for "things" and not for verbs? When I translate it to Dutch it also sounds rather strange to use "niet mogelijk" (nicht möglich) instead of "onmogelijk" (unmöglich). Do you have that too in German?

[sister-luck.livejournal.com]

There are lots of possible constructions for possible, just not the one above. Among other things that work are "it + be + possible (+ for + object) + infinitive" and possible with a that-clause introduced by it. It's really rather weird.

In German we can both say Diese Mengen zu essen ist unmöglich. and Diese Mengen anzubauen ist nicht möglich and I guess that's how this sentence came about. A construction with Es ist unmöglich/nicht möglich.... works, too.

Now I'm wondering about
To eat this amount isn't possible

I can't quite decide whether that's well-formed or not.