One thing I wanted to ask you is, what's your understanding of the word
and what's your academic background with regards to the Japanese language?
I took a couple of college-level courses, never lived in Japan or developed any fluency. But the way I understand it, kanji are evocative of meaning and not descriptive; meaning is highly dependent on context, and in some areas of Japanese thought, the context is such that there are several meanings at once.
Sure, while my undergraduate degree is in Electrical Engineering, I have a minor in Japanese language, with 32 credits in Japanese. I also spent a semester at 国際基督教大学 (International Christian University), and probably have spent a year and a half in japan in total with offers to work in an total japanese environment in both engineering and intellectual property (sorry, no eikaiwa work for me, but the Japanese still don't pay well enough compared to the US for engineers). I also spent a semester studying chinese, and I am learning at home as my inlaws don't speak english.
While I studied the language, I did not spend a ton of time on the history of characters, learning the meanings of radicals is a biproduct of the higher level courses where you spend a fair amount of time looking up kanji in a kanji dictionary. Going by radical gives you a hint of an interpretation of the character, but given that so many are in a more simplified form, the "story" may not quite be correct in terms of the origin, but may be good as a memonic device.
Lets look purely at the radicals of ai and ki, while not all kanji are pictograph's the radicals do tell a story. For those reading this thread, who are unfamiliar, radicals are the constituent components of the chinese characters, each of which have their own meaning.
For "go", awa(su), a(i), Nelson's japanese-english character dictionary uses kuchi (mouth) a 3 stroke radical as the root. When looked at pictorialy, the character is considered to be a rice pot with a lid, however the other 2 radicals are jin/hito and ichi, one. A lit fits on a pot, and joins the two together.
For "ki", you have three radicals, the bottom one is rice, the second is a lid, and the top one is air. Thus it pictorally represents steam coming off of rice with a lid on it, or pressure/air pressure. In chinese it can mean vapor or steam, in addition to its normal meanings in japanese..
So asides from the rice fixation, a given since it is staple, we have joining of air pressure. This idea of air pressure in a martial context is very important, as air pressure is used to not only condition tissues, but initiate movement from the middle (tanden/hara centric movement) and power that movement from the middle on out. I'm not going to go into the whole chinese cosmology of this, but you can read up on that on your own.
Thus through the use of air pressure and movement from the "middle", you join with the opponent to create aiki.
I can pull out my 国語辞典, if you want for a japanese to japanese definition, if you think it would be helpful to this conversation. None the less I'm hardly the first person to bring up this topic.
Or maybe if you eat a lot of rice you get a fat bellly :P
One thing that has always perplexed me about
is to what extent it carries a meaning of unity
as opposed to a joining of different things.
I.e. when "two" things come together - is this two things joining into a new whole, or is it as two halves reuniting into one thing.
Well, I can't speak on a scholarly level with regards to the entomology, as my minor is more in the usage and study of the language in a practical basis. My personal opinion is that its two things joining to create a new hole, in a martial context, but given that there are multiple meanings, I can't say which is more "correct."