Owning a truth for a limited period of time in return for telling everyone instead of keeping it a secret is not absurd. Society would rather you tell people so people can build on it (at least in noncommercial ways, or via license) while you own it than keep it secret, so we created the patent system. The alternative could easily be trade secrets until you die and never reveal it, and as a society we decided to incentivize you to not do that