We propose an approach to quantum theory based on the energetic causal sets, introduced in [M. Cortes and L. Smolin, arXiv:1307.6167]. Fundamental processes are causal sets for which the events carry momentum and energy, which are transmitted along causal links and conserved at each event. Fundamentally there are amplitudes for such causal processes, but no space-time. An embedding of the causal processes in an emergent space-time arises only at the semiclassical level. Hence, fundamentally there are no commutation relations, no uncertainty principle and, indeed, no h. All that remains of quantum theory is the relationship between the absolute value squared of complex amplitudes and probabilities. Consequently, we find that neither locality nor nonlocality is a primary concept; only causality exists at the fundamental level.