2026-07-072026-07-07http://salesiana.dossiersoluciones.com/handle/123456789/150481Dynamical systems can be quantised only if they are Hamiltonian. This prompts the question from which our talk gets its title. We show how the simple predator-prey equation and the damped harmonic oscillator can be considered to be Hamiltonian with respect to an infinite number of non-standard Poisson brackets. This raises some interesting questions about the nature of quantisation. Questions which are valid even for flows which possess a canonical structure.4 pages standard LaTeX. To appear in proceedings of International Conference on Chaos and Dyamical Systems - Tokyo Metropolitain University 23rd-27th May 1994. To be published in Advanced Series in Dynamical Systems of World ScientificChaotic Dynamicstext