The Church-Turing Thesis is a fundamental concept in computer science and mathematics that proposes a definition of what it means to compute something. It suggests that any function that can be computed by a human using a clear set of rules can also be computed by a theoretical machine, known as a Turing machine. This idea connects human reasoning with mechanical computation. This thesis was developed independently by Alonzo Church and Alan Turing in the 1930s. It implies that all computational problems can be solved by these machines, establishing a foundation for modern computer science. Essentially, if something can be calculated, it can be done by a Turing machine, reinforcing the limits of what can be computed.