Blockchain and Common Knowledge

Jan Xie
Jan Xie
Nov 15, 2018 · 4 min read

The blockchain is a very special kind of distributed database. Before the blockchain, we would not see two or more companies sharing a distributed database collectively, let alone using this database to verify the integrity of each other’s information.

The primary design goal of a distributed database is to section data (sharding) to improve overall system throughput. However, a public blockchain’s goal is to form consensus and maintain trust; this difference in design goal ultimately affects the final system design.

One of the basic assumptions of a public blockchain is that nodes in a system do not need to trust one another. These untrusted nodes can be unreliable, controlled by hackers, or even could be running modified software that does arbitrary things.

It is a public blockchain protocol’s responsibility to lead these untrusted nodes together to form global consensus and more importantly, to establish common knowledge.

Common Knowledge

Common knowledge is information that is accepted by a group of people, but not only does this group have a common knowledge, they also know that other participants in the group have the same knowledge and know that the other participants know all participants have the same knowledge too. Although this concept sounds a bit strange, we see it play out in our lives every day.

For example: If you are a foreigner and this is your first time visiting China, when you step into the elevator of a building and find out there is no 4th floor or 14th floor, you may feel confused and wondering why. But this confusion won’t happen to a local because, in Chinese culture, most people believe that 4 and 14 are unlucky numbers. Not only are businesses aware of this, but the people who construct and sell buildings have this knowledge as well. To demonstrate the dynamic of common knowledge, when tenants look at the design of the building, they do not attribute the absence of the floors labeled with 4th or 14th floor to a failure on the part of the building’s construction or design firms, they refer to their common knowledge and will not complain to officials about the missing 4th and 14th floors — this is where we see the broad trust that is established with common knowledge.

Common knowledge can be objective (mathematics), or it can be subjective (rules created by people). It can be said that all laws and regulations are forms of common knowledge.

Value is such subjective common knowledge that it only exists in people’s minds. Value stems from what most of us think is valuable and what we know others will agree is valuable.

Why do I see blockchain as a common knowledge base?

Joining a blockchain network means contributing to the consensus process and data verification, as well as accepting that the state with the consensus of the nodes is valid. After a transaction is verified by a node, it is broadcasted to all the other nodes in the network and saved along with the relevant timestamps and certificates. Every node in the blockchain acknowledges that the transactions in the blockchain are valid and knows that other nodes will recognize these transactions as valid as well.

The idea of Bitcoin was to create a public accounting ledger that records who owns what and keeps track of all transactions. Money is the common knowledge stored in the Bitcoin ledger. At Nervos, we want to take this one step further and store more kinds of common knowledge (e.g. digital assets, smart contracts, crypto proofs for arbitration, identities, etc.) on Nervos CKB.

The goal of Nervos CKB (Common Knowledge Base) is to reach consensus on an arbitrary global state and store it. We call this Common Knowledge Base because it is a stored state with global consensus. Global consensus is slow and expensive and that is why we should use it wisely.

One role Nervos’ CKB can play well is similar to a court’s function, where universally agreed upon rules are enforced and records are archived. Because everyone has the same awareness of this common knowledge and abides by it while participating in Nervos Network, we can trust each other and seamlessly cooperate on activities.

In game theory, common knowledge is the basis of collaboration. Common knowledge is the foundation used by people to anticipate their counterparts’ next move. With more accurate predictions of others’ actions, people can better identify the strategy that fits their needs and actively lower their risks. Sharing more common knowledge between parties allows for more confident and lower cost collaboration, increasing efficiency across a society.

If we could improve the creation and dispersal of common knowledge, even if only by 1%, our lives would change drastically. In the past, we established oral and written common knowledge.

Today, we have new technology for automated global consensus, mutual verification, and reliable state transfer and storage, and we see the possibility to industrialize the production of common knowledge.

With the help of cryptography, the common knowledge on a blockchain not only exists among humans but also between human and machine, as well as between machine and machine. We are not only making common knowledge creation more efficient, but also distributing it more widely.

The internet allowed our communication range to expand to a global scale and enabled us to meet strangers on the other side of the planet. A common knowledge base will extend our trust boundary to new frontiers we have never seen before.

Nervos Network

The Nervos Network is a public blockchain ecosystem and collection of protocols aiming to solve the current challenges facing blockchains like Bitcoin and Ethereum today.

Jan Xie

Written by

Jan Xie

Nervos / Cryptape

Nervos Network

