I heard somewhere that it was the Maharal or a similarly philosophical author who wrote that the definition of good is "something that serves its purpose." It has been escaping me for quite some time, and if I could get a definitive answer or, even better, be pointed to the source, that would be much appreciated! Thank you!
1This definition does not seem understandable. The definition of good would seem to be not subject to a brief writeup. It would seem to be a full book at least.– sabbahillelNov 12, 2020 at 2:29
I talk about the fact that "טוב" (and, for that matter "good") means both moral good and functional good ("this is a good pen") on my blog at aishdas.org/asp/ethics-and-morality . But I didn't have a source; I reasoned it out from the use of the same word, and how the shoresh appears in expressions like "hatavas haneiros".– Micha BergerNov 12, 2020 at 17:35
Are you possibly referring to the Maharal in his commentary on Pirkei Avos (Ethics of the Fathers) entitled Derech Chaim.
In the first chapter and second Mishna of Pirkei Avos the text reads:
שִׁמְעוֹן הַצַּדִּיק הָיָה מִשְּׁיָרֵי כְנֶסֶת הַגְּדוֹלָה. הוּא הָיָה אוֹמֵר, עַל שְׁלשָׁה דְבָרִים הָעוֹלָם עוֹמֵד, עַל הַתּוֹרָה וְעַל הָעֲבוֹדָה וְעַל גְּמִילוּת חֲסָדִים:
Shimon the Righteous was one of the last of the men of the great assembly. He used to say: the world stands upon three things: the Torah, the Temple service, and the practice of acts of piety. (Sefaria translation)
The Maharal on the boldened part of the Mishna discusses why specifically these three things the world stands on. As part of his analysis he writes the following here:
כי הנבראים נבראו בשביל שיש בהם הטוב, ואם לא היה בנמצאים הטוב, לא היה נבראים. כי הדבר שאינו טוב בעצמו, אין ראוי שיהיה נעדר, ולא יהיה לו המציאות. אבל מציאותו בשביל הטוב שיש בו וכמו שבריאותו הוא בשביל הטוב, מכל שכן קיום העולם ועמידת כל הנבראים הוא מפני שנמצה בהם הטוב. ואם לא היה נמצא בנבראים הטוב לא ראוי להם הקיום, רק מצד הטוב שנמצה בכל אחר יש לו קיום, ומפני זה חתם בכל בריאה ובריאה במעשה בראשית (בראשית א:ד) וירא אלקים כי טוב
Since the creations were created for the sake of having the good in them, if it was not found in them to be good, they would not have been created - Because the thing that is not good in itself isn't fitting for it to be missing/lacking, and it would not be in reality. But its reality is for the good that is in it and just as His creation is for the good, all the more so the existence of the world and the standing of all creations is because of the good found in them. And if the good was not found in the creations, it is not fitting for their existence - only from the side of the good found in it all does it exist . And because of this, He signed it (i.e. this attribute of having good) in each and every creation in the creation of the world (Bereishis 1:4) "And G-d saw that it was good".
This can be sourced in the Ramban.
The first time we find the word "good" in the Bible is in verse 4- וירא אלקים את האור כי טוב. The Ramban there as well as several other places explains that the "good" that G-d "saw" was "קיום המינין לעד" which means G-d saw that what He built was something that would serve its purpose forever.