IN THOSE parts of the planet that might once have been described as “Christendom”, this week marks the season of peace on Earth and goodwill towards men. A nice idea in a world more usually thought of as seasoned by the survival of the fittest. (from Economist.com)

I was just wondering if anyone could explain why 'world' is used here with the indefinite article rather than with the definite one. 'A world' has been already implicitly specified in the first sentence since we have references to the planet and Earth. Furthermore, in the second sentence we also imply that we know which world we are talking about: notice the reference to thoughts and seasoning.

Thanks a lot,

I think the model for this usage of the indefinite article is as follows.

The sun is actually a star.

The house I live in is a large mansion.

This pencil is a red pencil.

This pencil is a pencil which can be used to write in red.

The frightened children ran into the dark warehouse. It was a dangerous place for them to be.

These all have to do with subcategorizing. "The X is a Y", i.e., "The X is a kind of Y" or "This X belongs to a category called Y" or "X is a member of Class Y"... or various other paraphrases which you may supply as desired.

In the case at hand, we have, more awkwardly expressed to show the pattern,

"This week marks the season of peace on Earth. This is a nice idea (in this world). This world is a world thought of as seasoned by the survival of the fittest"

Nice explanation Emotion: smile I will have nightmares about (the) English grammar tonight. Emotion: smile