Before the birth of NFTs, assets in the blockchain industry mainly existed in the form of Fungible Tokens (FTs), such as BTC and ETH. As its name implies, this is a type of interchangeable digital asset where 1 BTC = 1 BTC. We can easily associate it with fiat currencies in the real world, such as USD, CNY, JPY, where 1 USD = 1 USD, and 1 CNY = 1 CNY. Therefore, FT assets are easy to understand, and regardless of whether we approve of them, as long as we say 1 BTC = 1 BTC, we naturally associate them with fiat currencies for understanding.
If we shift our focus to real life, we quickly realize that fiat currency did not initially exist in our lives, at least not like an apple tree or a cat that exists in the natural world. Our ancestors invented currency for the purpose of exchanging or trading goods and commodities. Soon, we became accustomed to living in a world where everything was measured by currency. For currency, we say that an old 100 CNY note is equal to a new 100 CNY note, which means 100 CNY = 100 CNY. However, we would not say that your 10-pound orange cat is equivalent to my 10-pound orange cat, even if they were born on the same day with the same facial features. You would say your cat is named Duo Duo and has an affectionate personality and doesn't like vegetables, while I say my cat is named Da Sha and is very silly. If you observe these two cats closely, you will find that they are completely different. Even for two newly produced Apple computers, which look identical in appearance, they would present completely different faces after being used by different people for years.
Therefore, real-world things often have uniqueness, and sometimes we can use the price of general commodities to measure them, but the previous currency price may become invalid when emotional or spiritual value is added.
After FT, NFT emerged.
Obviously, FT can say that 1 BTC = 1 BTC, but it cannot say that your 5-year-old digital cat and my 5-year-old digital cat are completely equivalent. NFT can solve this problem. Now, we put your 5-year-old digital cat on the chain and turn it into an NFT. You can write a lot of metadata about this NFT. You say that this digital cat is named Mi Mi, is a female, has brownish-yellow fur, and heterochromatic eyes, and so on, all kinds of information that only you know. When anyone queries this NFT, they will learn that this NFT belongs to you, which means you are the owner of this digital cat, and people can understand various information about this digital cat through its metadata, thereby generating emotional and other dimensions of cognition. Obviously, time is a developing concept, so things will also develop. For example, your digital cat will also change during the time it accompanies you, such as one day when you want to change its name from Mi Mi to Mei Mei. Therefore, even in the digital world, information is constantly changing, and the metadata in NFTs will also change over time.
NFTs solve the need to define the uniqueness of digital things in the digital world and also enable native digital assets to have uniqueness and ownership attributes through NFT technology (based on the premise that all things can be capitalized and monetized in the economic society).
Returning to the real world, we have seen that currency can exist in the digital world in the form of FTs, and now real-world tangible things can also exist in the digital world with uniqueness through NFTs.