Rujo:Erinja said: "Every experienced speaker in this thread has said not to use aĵo for something non-concrete."
Are you talking about experienced speaker in English or in Esperanto? I don't know about your experience in Esperanto and you don't know about mine in it. You may only conclude about my capacity in English, because it is you mother language, I suppose.
Dear lady, I am not your enemy. I'm just a Third World esperantist seeking a fraternal environment to discuss issues. If I have offended you anyway, young lady, it’s because I do not dominate the language of the powerful country all over the world.

Obviously I meant experienced speakers of Esperanto. Someone who thinks it's normal and common to use "aĵo" for something non-concrete in Esperanto is obviously not an experienced speaker. No offense. If they are an experienced speaker, I have no idea who they have experience talking to, because in my years of talking to Esperantists all over the world, I haven't encountered this usage in experienced speakers from any country.

I am not sure why you're talking about the third world. Economic status of various countries doesn't relate to Esperanto grammar, in my opinion.

Erinaj is right to distinguish between afero and aĵo, with aĵo (the word) being largely used for concrete objects.

However there are instances in the Tekstaro where aĵo has been used for 'thing' in a more abstract sense; several in Metropliteno, and I spotted a recent one in Artikoloj el Monato:-

Mi frakasis lian novan veturilon en trafika akcidento: tiaj aĵoj okazas

A particularly ticklish one for re-formulating is:-

memoru, ke la afero koncernas du aliajn aĵojn: mian propran haŭton kaj la rekompencon