- a problem that a common computer can solve (given enough memory), will also be solvable using a Turing machine - invented by [[Alan Turing]] - anything this can compute, can also be computed by [[Lambda Calculus]] - analogies to real components: - tape -> [[RAM]] - head -> [[CPU]] - instruction list -> [[SSD]] (memory) https://brilliant.org/wiki/turing-machines/ https://www.youtube.com/watch?v=dNRDvLACg5Q&t=32s