All physical theories are computational so the models of the universe are technically some model of a computer. Classical Hamiltonian mechanics is a computational model, as are all further generalizations like quantum mechanics. If a physical theory was not computable then it couldn't be used for controlling GPS satellites and landing rockets after lift off. In fact, it would be very interesting if there was a non-computational model of physics that could be used to make predictions about physical reality like planetary trajectories.<p>This is why it's kinda silly to claim the universe is a computer because there is no competing predictive model of physical reality that is not computational.