Lambda-CDM's Big Bang model predicts that distant regions of the cosmic microwave background should have had no time to exchange light or heat with each other before recombination, yet observations show these regions have nearly identical temperatures to one part in 100,000. The standard resolution invokes cosmic inflation, which stretches a causally connected patch to enormous size. However, inflation itself requires fine-tuning of initial conditions and introduces conceptual problems: what caused inflation to begin and end? Without inflation, the horizon problem appears unsolvable within the hot Big Bang framework, as causality and light-speed limits seem to forbid thermal equilibration across the observable universe (Guth 1981; Kolb & Turner 1990). SCT eliminates the need for inflation entirely by replacing the singular hot origin with a different causal structure.