Fitch's theorem

Fitch's theorem states that if a logical argument’s conclusion follows necessarily from its premises, then the argument can be verified through a systematic process called Fitch-style proof. This method involves step-by-step logical deductions that demonstrate each conclusion is directly supported by earlier steps. Essentially, it provides a structured way to confirm that a conclusion logically results from the assumptions without any gaps, ensuring the reasoning is valid. Fitch's theorem guarantees that any valid logical argument can be checked and validated within this formal proof system.