I heard my friend, a researcher, say that we can, in theory, explain every event happening in the universe using the Conservation of momentum and energy. He added that we may not be able to do that "now" as we do not have all the variables required to describe the Universe completely.
My question is: 1) Is it possible to explain everything(including emotions of humans) if we are given all the variables, laws of conservation of momentum and energy and a computer that perform calculations at incredible speeds? (Note: the governing equations of system dynamics is not known, only the states and the conserved quantities)
Give a simple example, if the answer is "No".
Give a reference to a valid proof if the answer is "Yes".