Today we discus another core feature of the blockchain ledger, immutability.
In previous articles I discussed that the blockchain is a ledger or record of transactions. Link. I also explained that because the transaction is the record, it is 100% accurate everytime.
Then we talked about another core principle of the blockchain, transparency of the blockchain record, and the blockchain explorer. Link. In that article I talked about how the blockchain is transparent, in that you can see all the transactions on a software application called the blockchain explorer.
So today we will cover another important core charactristic of blockchains Immutability which means unchangeable and whay this is important.
Changing the Ledger or Record of Transactions
The blockchain is a Book or Ledger of account of all transactions to date.
It is accurate because the way your conduct or perform transactions also records those transactions.
In traditional Ledgers the entries are in pencil, so they can be changed, if they are later found to be a mistake.
Modern Ledgers are digital, and they also can be changed later if the entries are found to be in error or an error.
Blockchains however are not written in pencil, they are digital like Bank records. However unlike bank records the digital record of the blockchain cannot be changed, erased or altered. This is one of the blockchains strongest strengths, and also one of it's relative weaknesses according to some.
Let me explain.
Example:
You go to the bank and you deposit your paycheck of 2000.00 dollars.
In an American Bank you fill out a deposit slip, writing your bank account number, the date, and the amount of the check, along with the check number.
Then you attach your signed paycheck and this deposit slip and hand it to the bank clerk.
The clerk pulls up your account on their computer and types in a deposit 200.00 dollars.
Then the clerk adds that amount to your account balance and prints out your balance, and hands that to you on a receipt, which shows you added 200.00 to your account balance and your new balance.
You look at the receipt and realize immediately that the bank clerk added the wrong amount; instead of 2000.00, they added 200.00.
You point out to them that they added the wrong amount, therefore your account balance is wrong.
The clerk looks at your deposit slip and sees 2000.00.
The clerk looks at your paycheck and sees 2000.00.
The clerk looks at your account transactions and sees 200.00 with todays date and the paycheck number, and realizes the paycheck with that number is 2000.00.
The clerk goes back into the Ledger or Record of account and changes the deposit of 200.00 to 2000.00 and corrects your account balance.
So ask yourself how often does this happen, and is it always corrected?
How many people lose money this way?
The clerk at that bank, the manager, and several other bank officials have the ability to change the ledger.
We really rely on the bank ledger, and because it can be changed so easily, we have to trust the bank to do the right thing.
So ask yourself is this bank ledger really accurate?
And is it okay that it is so easy to change the ledger?
The Problem and the Solution
This ability to change the traditional ledger is a feature, which is positive, but also a big problem, because it calls into question the correctness, accuracy or reliability of the ledger or record of transactions.
So we are left trusting the people who have the ability to change the Ledger to Do the right thing.
So blockchain solves this dilema by making it very hard to change the Ledger.
The Ledger is created by transactions and the transaction is the record.
You literally can't make a mistake in the entry on the Ledger.
The entry will reflect exactly what you did, and you are responsible for typing in what you want to happen, and your transactions are final.
The blockchain ledger is not changeable, and this inability to change the ledger is a feature, not a bug, and it's called immutability.
This is a core concept that the ledger should never be changed, and it you do it takes a vote of all the people running the computers which run the software which keeps the ledger, and such a vote results in a huge event called a Fork.
A fork occurs when you want to go back in the ledger before certain transaction or transactions were recorded and start recording transactions again at this point, creating a new ledger which doesn't contain the transactions you don't want to be a part of the ledger.
The old ledger stops at the date you started the new ledger or forked the ledger / blockchain. The old ledger is still there and now you are recording transactions on a new ledger.
Forks can and do cause a great deal of division in the community.
The most famous was the Fork of Ethereum into Ethereum and Ethereum Classic.
They forked the ledger to correct a large theft of tokens, but this compromises a basic core principle called immutability.
Once you make this practice a tool to use you are on a slippery slope in a way, as you are now doing the same thing traditional ledgers do and changing things after the fact, something which goes against the very reason blcockchains exist.
However, a Fork can be a way for a large divided community to peacefully disagree and part ways. Each community going their own way after a big disagreement. A Fork can also preserve history, the two communities just start recording on a different fork of the ledger which contains different rules and they sometimes rename one of the forks and rename the token for one of the forks. In this way immutability is preserved.
That history will be forever present and the Community carries on on separate ledgers.
Last Words;
Immutability or the inability to change the ledger is an important part of the digital blockchain ledger, as it replaces Trust. This combined with the fact that a transaction is the record, makes blockchain ledgers inherently trust worthy.
In the absence of immutability, a blockchain becomes just another trusted ledger.
