Computers use binary logic because it simplifies design and implementation, relying on two distinct states (0 and 1) that facilitate reliable switching. Early computing systems favored binary due to its straightforwardness, making it easier to develop programming schemes that are efficient and effective. Introducing ternary or multi-valued logic would complicate processing speed and system architecture without significant advantages in most applications. While tri-state logic could represent more values, the complexity it introduces often outweighs its benefits. Overall, binary remains the simplest and most practical choice for computing systems.