Caption: A six-story card castle (or "house of cards") made from 3.5 decks of playing cards." (Slightly edited.)

This looks like a faux house of cards to me.

Remove one card from a house of cards almost anywhere without great care and it falls. A theory is like a house of cards: disprove one absolutely determined result based on the theory and the theory is falsified.

The conclusion is that we can trust the results of a well-established theory that are NOT directly verifiable---the whole theory would be wrong if they were wrong---and very probably it is NOT wrong since it's well established.

The analogy between a theory and a house of cards is NOT perfect, of course.

A good theory should have few axioms and infinite results. A house of cards has many 1st storey cards compared to the number of cards in any upper storey.

Actually, reality in most respects is verified by overall consistency of behavior, NOT by checking every event. If any theory about anything that we depend on for many effects was inadequate, we'd notice---and have to correct said theory or replace it.

Credit/Permission: Jesse Merz (AKA User:Merzperson), 2007 (uploaded to Wikipedia by User:Liftarn 2007) / Public domain.
Image link: Wikipedia: File:Card castle6.JPG.
Local file: local link: house_of_cards.html.
File: Art_h file: house_of_cards.html.