Aki Eda's perspective on love and her putting it to story is always dazzling, and this manga is no exception. Like always, the artstyle is a thing of beaut, and the characters are so, so mostly charming. The thing that captured my heart the most was how the characters expressed their own feelings - eloquent and authentic. The ending wrapped up everything decently and is overall just a perfect last piece for the puzzle called "love" this manga was trying to solve. Anyone who have a different notion on how that puzzle should be solved, will inevitably disagree with the author's.
I'm one such person. It's day and night how everything was so nicely set up in the first half, only to be bizarrely torn down in the second. Love is subjective, sure, but this manga just leaned way too hard into it to the point of self-indulgence and vanity. The chemistry between the male lead and all female leads is non-existent - just because you (the manga) acknowledge it does not mean it isn't there and you shouldn't improve upon it. Love, in this manga's blind pursuit to define it, was carried out terribly. Every other factor suffered as a result. Koi wa Hikari is anything but an enjoyable story - an interesting literature debate? Sure! But it's so frustrating seeing all the potential around the premise and world-building gets plateaued by the main cast's passiveness and looping in place - all just to reach an alien and unsatisfying conclusion. I truly appreciate the author always trying something new in all of her works. But if you want to read a truly thought-provoking, no, just a pleasant piece of art, you're better off looking somewhere else.