Not just possibly. Here's a non-exhaustive list of models of computation that are all equivalent. + Turing machines + Lambda calculus + General recursive fun

Not just possibly. Here's a non-exhaustive list of models of computation that are all equivalent. + Turing machines + Lambda calculus + General recursive functions + Mu-recursive functions + SKI calculus + Pi calculus + Register machines + The semantics of essentially every mainstream general programming language This remarkable profusion of equivalences is the main reason why the Church-Turing Thesis (an informal statement that our intuitive notion of computation coincides with Turing machines and/or the lambda calculus) is commonly accepted.