It is a heterodox school of thought, rooted in the work of John Maynard Keynes and Michal Kalecki, that emphasises the principle of effective demand where output and employment are determined by aggregate demand rather than supply constraints. It challenges neoclassical assumptions of self-correcting markets by foregrounding fundamental uncertainty, the importance of historical time, and path dependence, arguing that long-run outcomes are shaped by a sequence of short-run dynamics rather than independent equilibrium states. It highlights how the trajectory of an economy following shocks is crucial, thereby underscoring the need for active policy intervention and demand-led growth to address real-world issues such as instability and inequality.