Bitcoin's Turing Incompleteness

Atharva MaskarAtharva Maskar
3 min read

Ever since I started learning Blockchain I've struggled to find a straightforward and code-free explanation of Turing incompleteness in Bitcoin. So, here's my attempt to break it down using simple and uncomplicated words.

What is a Turing Machine?

Before we talk about Bitcoin's Turing incompleteness, Let's first discuss and learn what a Turing Machine is. Imagine a magical machine that can solve any problem you throw at it, as long as it can be solved with a set of instructions. That's the Turing Machine! Alan Turing, the genius behind this concept, dreamed up a theoretical machine that could compute anything you can think of, as long as you can break it down into simple steps.

What on Earth is Turing Completeness?

Turing completeness, therefore, refers to a system or language that possesses the same computational power as a Turing Machine. In simpler terms, it can solve any problem that can be solved using an algorithm. So when we say Bitcoin is Turing incomplete, we're basically saying it's missing a few screws in the algorithmic department. Its creator(s) envisioned a digital currency that would free us from the clutches of centralized financial institutions. However, in their quest for decentralization, they made an interesting choice: to keep Bitcoin Turing incomplete.

Why, you ask? Well, let's put on our sarcastic hats and explore a bit. Who needs the power of a Turing-complete language when you can have an unpredictable, slightly quirky cryptocurrency? It's like having a car that can't do U-turns or a smartphone that can't take selfies. It's frustrating, but it's so uniquely Bitcoin.

everyone knows turing-complete is "safe" - Dr Evil Austin Powers | Make a  Meme

Why is Bitcoin Turing Incomplete?

To understand why Bitcoin is Turing incomplete, we need to take a closer look at its scripting language. It is intentionally limited, lacking loops and arbitrary branching.

In other words, you can't create complex programs or execute any arbitrary algorithm within the Bitcoin network. The scripting language is like a box of crayons with only a few colors - yes, you can draw beautiful pictures, but you're limited by the palette available to you.

The decision to make Bitcoin Turing incomplete was not a random one. By limiting the scripting language, the creators aimed to enhance the security and robustness of the network. It's like building a sturdy castle with a narrow gate - sure, it limits the possibilities, but it also keeps out unwanted intruders.

Bitcoin's creators didn't want malicious actors exploiting the network with potentially harmful code. By keeping things simple and predictable, they prioritized safety and reliability over the boundless freedom of a Turing-complete system. And hey, if you're going to build the backbone of a financial revolution, you might as well do it with some caution.

Epoch 3: Solving problems by searching | by panutanu R | Medium

Conclusion

So there you have it, the tale of Turing Incompleteness in Bitcoin. It's a fascinating feature that sets Bitcoin apart from other cryptocurrencies like Ethereum. While Turing incompleteness may be frustrating for those seeking limitless programmability, it also ensures a level of security and stability in the network.

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Written by

Atharva Maskar
Atharva Maskar

Blockchain Developer | Web3 | DeFi