You might have heard of the word “Subjectivity” and do not know subjectivity definition and meaning, this article is for you. In the article, we will talk about weak subjectivity.
Subjectivity definition and meaning: what is weak subjectivity?
The term "weak subjectivity" was coined by Vitalik Buterin. It explains the need for nodes in a proof-of-stake (PoS) blockchain to depend on other nodes. Nodes do this to figure out the current state of the system.
First, let's define objectivity and subjectivity in the context of blockchain. These ideas are related to the premise that, as distributed systems, blockchains often have multiple legitimate chains. Basically, this means that there are many ways to get from the genesis block to the nearest block. Also, all methods are valid.
Objectivity can be defined as the ability of new nodes to join the network. Among other things, it can quickly identify which chain is active (or longest).
Subjectivity is associated with blockchains that can be interpreted in a number of ways. This is so because their consensus mechanism is influenced by a "social network" that relies on node interactions.
Weak subjectivity means that subjectivity is unacceptable for short time spans, but acceptable for long time spans. Specifically, it is recommended that if you have a continuously online node, you will be able to automatically determine the correct ledger, but if your node is offline for months, you may need to get information from other people (eg friends) using a node that is online or block explorers) to determine the correct ledger.
Thus, when trying to identify the current state of the ledger, subjectivity is tied to the premise that some nodes need information from other nodes. This has nothing to do with reaching consensus. Rather, it has to do with identifying which chain is active.
Essentially, this is necessary for blockchains that use a proof-of-stake model. In summary, weak subjectivity is used to determine which chain is active. Essentially, it's considered weak because it only happens in two cases:
- When a new node joins the network
- When the node is offline for a long time
So I hope now you will understand Subjectivity definition and meaning: What is weak subjectivity. If a node is always online, then subjectivity is not a problem. Simply because it will be able to instantly identify which ledger is legitimate. However, if a node is offline for a long time or just joined the network, it has to rely on other nodes. This is when subjectivity comes into play.
