In such a setting there was no notion of "property" at all beyond brute force. Eventually it was discovered that greater things can be accomplished when people adopt the polite fiction that taking something doesn't always make it yours.

If you don't believe that then try to declare independence over your garden and claim that since you are now a sovereign state you no longer need to pay tribute to the country that now surrounds yours.

Though it feels like I'm bringing a pen to a flamethrower fight, I'll attempt to clarify.

In describing property as a "polite fiction" I am acknowledging that it is not real. Brute force is as real as it ever was, but in practice the abstraction of property means it is usually the option of last resort. We've all benefited from that. To wit, I consider the present notion by contrast a few degrees beyond (more advanced than) brute force, though you are right to say that it is not beyond (free of) brute force.

So, to venture back to the original context from which we've so far strayed: although you try to cast the concept of intellectual property in an absurd light by putting it into an era of development in which it did not and could not exist, it remains true that the more fundamental concept of property was crucial to the same development beyond that era you claim intellectual property would have prevented. We grew by adopting a fiction, and now have an abundance of recorded history indicating that being a "figment of our collective imagination" is not a bad thing when it reflects the human perception of value better than reality. I trust you can see the parallel in the three centuries that ownership of a book has been distinct from the ownership of a copy of the book, or that at the very least you would not regard our intellectual development in that time as having languished.

We would not have culture or have achieved the level of society that we have if 'intellectual property' were the normal mode and could be deduced from first principles.

Copyright and patents are supposed to foster creation and innovation but it seems they are hindering rather than helping our development in these areas.

Well. Some of these follow when you accept certain axioms and work from there. Not everyone accepts those axioms (at at least the same ones), if the vast variance in "human rights" across the globe is any indication.

Now of course it can be argued that only a few countries in the "civilized western world" understand logic and can come up with the proper first principles. (People have told me that)

In a good system you don't care on which side of the ledger you're on, which is something that that same logic would allow you to deduce.