In your world who is the "ultimate authority of everything"?
For me, there is no ultimate authority on everything.
When I cook, I consult a recipe either memorized or in written form.
When I want to learn how to play a song on my guitar, I consult a music book.
When I want to learn about history, I consult a history book.
When I get a toothache, I go see a dentist.
When I want to buy some running shoes, I go to the store and let my feet determine what shoes feel best - not the shoe sales person.
When I need gas, I check my phone app to see who has the lowest price.
When my computer is acting sluggish, I use my technical knowledge to resolve it
When I want to learn about the universe, I consult a science book.
When I need my car fixed I consult a reputable mechanic.
When I need tires, I usually buy the same tires that I currently have because they have shown to last a long time and perform well in wet conditions.
When I buy clothes though, I don't consult GQ or Esquire though. I prefer to look plain.