normal-2
Explanation
This comic contrasts how a "Normal Person" and an "Economist" interpret the same phrase. Both say "I could never put a price on the love of my child," but they mean completely different things. The normal person means it sentimentally -- their child's love is beyond monetary value. The economist, however, takes "I could never put a price on it" as a practical problem: since they personally can't determine the price, they'll need to use an auction to let the market decide.
The humor lies in the economist's inability to accept that something might simply be priceless. In the economist's worldview, everything has a price; the only question is the mechanism for discovering it. This is a classic SMBC joke about how economists apply market logic to domains where most people rely on emotion and sentiment. The auction suggestion is absurdly clinical -- treating a child's love as just another commodity to be valued by competitive bidding.
This fits into a long tradition of jokes about economists being so steeped in rational-choice theory and market thinking that they lose touch with basic human sentiment. The phrase "we'll have to determine it via auction" is the punchline because it reveals that the economist never considered NOT putting a price on it -- they only considered the methodology problem.