<p>Even though they are still somewhat negligible to miners today, transaction fees play an important role in the protocol known as Bitcoin, and will play an increasing role in the future.  Just look at all the questions this SE site gets about unconfirmed transactions.  Asking how the protocol works when removing all direct mining incentives is redefining the protocol in a major way.  It's like asking how HTTP would work if you remove the <a href="https://developer.mozilla.org/en-US/docs/Web/HTTP/Methods" rel="nofollow noreferrer">verbs</a> from the protocol.  At that point, it's something completely different.</p>

<p>When you remove such a critical part of the protocol, it's difficult to replace with something that works.  For example, your proposal of doing a proof-of-work on top of the last block hash as part of the transaction will effectively break the ability to use the protocol for smart contracts.</p>

<p>You are essentially asking what happens if you remove critical parts of Bitcoin, but still use the basic idea rather than creating a new protocol to match your paradigm of no mining rewards.  To that, I can only speculate that such a system is doomed for failure.</p>

CC BY-SA 3.0
2017-01-09T22:31:52.303Z
2017-01-09T22:31:52.303Z
Jestin
<p>If the mining reward was suddenly changed to 0, and there were no mining fees anymore, what would happen with the Bitcoin network? Assume there is another anti-spam measure in practice (ex: a tx would need the last block hash + some small PoW on top of it). Would Bitcoin suddenly collapse and get unusable, would it still operate normally due to voluntary mining?</p>

CC BY-SA 3.0
2017-01-09T22:03:49.187Z
Possible duplicate of [What will happen to mining after the 20 999 999th Bitcoin?](http://bitcoin.stackexchange.com/questions/5275/what-will-happen-to-mining-after-the-20-999-999th-bitcoin)
Jestin
CC BY-SA 3.0
2017-01-09T22:05:02.223Z
I marked this as a duplicate because it's not a matter of *if*, but a matter of *when*, and there's already some good answers.
Jestin
CC BY-SA 3.0
2017-01-09T22:09:30.117Z
@Jestin you're right, but my question was incomplete. I actually meant to ask what would happen if we removed any kind of mining reward, including fees. Basically, it is a thought experiment on which I want to know if the network could still operate safely solely with voluntary mining. I edited the question, could you remove the duplicate flag?
MaiaVictor
CC BY-SA 3.0
2017-01-09T22:15:39.783Z
in that case this question may be a little to speculative for Bitcoin SE.  This forum is best for questions with concrete answers, and not so great for thought experiments, speculation, or debates.  It's too hard for the community to determine what a "good" answer is.
Jestin
CC BY-SA 3.0
2017-01-09T22:16:05.193Z
Okay then, Jestin.
MaiaVictor
CC BY-SA 3.0
2017-01-09T22:32:59.853Z
It's a somewhat interesting question, so I took a stab at an answer.  Still, I wouldn't blame anyone for marking this as OT ;)
Jestin
CC BY-SA 3.0
2017-01-10T13:21:19.913Z
This question is not useful. The reward is part of the core assumptions of Bitcoin that you might as well be asking what would happen to Bitcoin if there were no internet.
Murch
CC BY-SA 3.0
2017-01-10T13:33:18.310Z
Okay then, Murch.
MaiaVictor
CC BY-SA 3.0
2017-01-10T16:56:18.247Z
Well, in a way that's perhaps actually the answer that you're looking for: Without a reward either through fees or block subsidy, the incentives of miners to rather support the network instead of attacking it don't hold. Miners wouldn't have a reason to spend irretrievable resources when they have nothing to gain. You'd need a different incentive or public fund to step in, and that would likely lead to centralization and/or other degenerations. –– I.e. it breaks the game theory of the Bitcoin system.
Murch
CC BY-SA 3.0
2017-01-10T20:09:01.247Z
@Murch but wouldn't large Bitcoin stake holders have an incentive to mine (at a loss) in order to protect the system? That is exactly what I'm asking: is it actually, factually known for sure that without the mining incentive the game theory is broken? I know the intuition strongly suggests that is that case, but has anyone actually proven it? Did anyone attempt to put a Bitcoin clone without the mining incentive?
MaiaVictor
CC BY-SA 3.0
2017-01-10T22:38:27.557Z
@MaiaVictor: Perhaps you should consider to either edit this question or ask a new question along the lines of "Could Bitcoin work without block subsidy and transaction fees?" IMHO that's a much more interesting question than "what would happen if Bitcoin stopped having a block subsidy and fees tomorrow". :) I'd vote to reopen that, and would write an answer on that.
Murch
CC BY-SA 3.0
2017-01-10T22:40:08.420Z
But there is already a good answer to the question as it is. I'll ask again.
MaiaVictor
<mining-theory>
What would happen if the mining reward suddenly became 0?
MaiaVictor
# What would happen if the mining reward suddenly became 0?

(Asked by: username_0 on 2017-01-09)

If the mining reward was suddenly changed to 0, and there were no mining fees anymore, what would happen with the Bitcoin network? Assume there is another anti-spam measure in practice (ex: a tx would need the last block hash + some small PoW on top of it). Would Bitcoin suddenly collapse and get unusable, would it still operate normally due to voluntary mining?

**Tags:** mining-theory

> **Comments:**
> **username_1**: Possible duplicate of [What will happen to mining after the 20 999 999th Bitcoin?](http://bitcoin.stackexchange.com/questions/5275/what-will-happen-to-mining-after-the-20-999-999th-bitcoin)  
> **username_1**: I marked this as a duplicate because it's not a matter of *if*, but a matter of *when*, and there's already some good answers.  
> **username_0**: @username_1 you're right, but my question was incomplete. I actually meant to ask what would happen if we removed any kind of mining reward, including fees. Basically, it is a thought experiment on which I want to know if the network could still operate safely solely with voluntary mining. I edited the question, could you remove the duplicate flag?  
> **username_1**: in that case this question may be a little to speculative for Bitcoin SE.  This forum is best for questions with concrete answers, and not so great for thought experiments, speculation, or debates.  It's too hard for the community to determine what a "good" answer is.  
> **username_0**: Okay then, username_1.  
> **username_1**: It's a somewhat interesting question, so I took a stab at an answer.  Still, I wouldn't blame anyone for marking this as OT ;)  
> **username_2**: This question is not useful. The reward is part of the core assumptions of Bitcoin that you might as well be asking what would happen to Bitcoin if there were no internet.  
> **username_0**: Okay then, username_2.  
> **username_2**: Well, in a way that's perhaps actually the answer that you're looking for: Without a reward either through fees or block subsidy, the incentives of miners to rather support the network instead of attacking it don't hold. Miners wouldn't have a reason to spend irretrievable resources when they have nothing to gain. You'd need a different incentive or public fund to step in, and that would likely lead to centralization and/or other degenerations. –– I.e. it breaks the game theory of the Bitcoin system.  
> **username_0**: @username_2 but wouldn't large Bitcoin stake holders have an incentive to mine (at a loss) in order to protect the system? That is exactly what I'm asking: is it actually, factually known for sure that without the mining incentive the game theory is broken? I know the intuition strongly suggests that is that case, but has anyone actually proven it? Did anyone attempt to put a Bitcoin clone without the mining incentive?  
> **username_2**: @username_0: Perhaps you should consider to either edit this question or ask a new question along the lines of "Could Bitcoin work without block subsidy and transaction fees?" IMHO that's a much more interesting question than "what would happen if Bitcoin stopped having a block subsidy and fees tomorrow". :) I'd vote to reopen that, and would write an answer on that.  
> **username_0**: But there is already a good answer to the question as it is. I'll ask again.  

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## 1 answers

### Answer by username_1 on 2017-01-09. Score: 2 | Accepted answer

Even though they are still somewhat negligible to miners today, transaction fees play an important role in the protocol known as Bitcoin, and will play an increasing role in the future. Just look at all the questions this SE site gets about unconfirmed transactions. Asking how the protocol works when removing all direct mining incentives is redefining the protocol in a major way. It's like asking how HTTP would work if you remove the [verbs](https://developer.mozilla.org/en-US/docs/Web/HTTP/Methods) from the protocol. At that point, it's something completely different.

When you remove such a critical part of the protocol, it's difficult to replace with something that works. For example, your proposal of doing a proof-of-work on top of the last block hash as part of the transaction will effectively break the ability to use the protocol for smart contracts.

You are essentially asking what happens if you remove critical parts of Bitcoin, but still use the basic idea rather than creating a new protocol to match your paradigm of no mining rewards. To that, I can only speculate that such a system is doomed for failure.


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