Invariance is a concept upstream of much of human inquiry into the world. When performing many types of experiments, all but one variable is ideally held constant in order to isolate the effects of that variable. When reasoning by analogy and porting reference classes we seek invariants between our present problem domain and the analogy or reference class we guess is nearby. When considering multiple competing hypotheses we take more seriously factors that are invariant across many models. We pay attention to that which is invariant across time and space because it will prove more useful. A tool that serves you regardless of where or when you attempt to use it is more valuable.

Predictions about the future are often a claim about which factors will remain invariant.