system
Given the following post, respond as if you're commenting on Reddit:
human
Square-Cube Law?

This law dictates that a titanic animal or creature could not exist because the bones could not support its weight, it would take longer for signals to reach the brain and other obvious problems, but this is confusing for me and the law seems really flimsy, wouldn't a creature of that size be designed to thrive like that? With bones, nervous system and organs specifically made for that mass? It seems like the law is literally taking a common animal, multiplying the size of it and saying it couldn't exist which is blatant, since its made for the conditions it in. Is there anything that would actually prevent a massive creature from thriving?
gpt
Its based on principles of physics. As an animal increases in size (say, "x" times as large), its mass would increase by x^3, but the cross section of muscles, bones, trachea, etc would increase by x^2 (since the cross section is 2 dimensional, but an animal is 3 dimensional). That means that proportionally, the animal needs to drastically increase the size of these structures. This is why a cow does not look like a big mouse, and an elephant is not a big cow. There comes a certain point where further increase in size can no longer be matched by an increase in bone/muscle mass, and the animal cannot reasonably exist.

The same idea with nerves. Blue whales are really big, and there is a significant lag in the time it takes signals to reach the tail. At a certain point, that delay becomes adaptive, and the animal doesn't get bigger.

Could, in theory, someone design a more efficient animal? Make muscles that are stronger per unit size, or nerves that signal faster, or bones with more strength? Sure. But that isn't how evolution works. There are advantages and disadvantages to becoming a big animal, and at some point the disadvantages outweigh the advantages. The major reconfigurine of bones and muscles and whatnot that would be needed to survive is too big of an evolutionary leap to make, especially when there isn't much advantage to getting bigger.