Every model has a foundation. Something everyone can accept as true. The more fundamental the foundation, the more general the model. It doesn’t get much more fundamental than physics, and causality is the most fundamental law physics has to offer. Even the ubiquitous “speed of light” takes the letter (c) from its true name: the speed of causality.  

The universe is basically a bunch of stuff (energy technically) that is constantly changing. In all of this, there has never once been an observation of an effect with no cause or a cause with no effect. Causality is always in effect. We can view the universe as a “causality engine”: a system that generates cause and effect at each instant. All the universe needs to “do” is to calculate the “next” positions and properties of each bit of stuff in the universe based on the “current” positions and properties of each bit of stuff in the universe. Then repeat this for tens of billions of years. Stuff happens. Can’t argue with that.