alt Hacker NewsThis website is absolutely nonsensical and I would not recommend it to anyone to understand how GAAP or IFRS accounting works. It might be useful for someone wanting to learn unicorn fantasy land accounting.
Double-entry accounting is basically checksum. For any transaction, the total in and out of all accounts involved in the transaction should be zero. If it's not, you have an error.
Conceptually, one of the hard parts to grasp and what many accounting students struggle with in the beginning is that in accounting financials, asset accounts have the opposite polarity as revenue accounts. This is because revenue is treated as an item that flows into Equity (in the famous equation Assets = Liabilities + Equity). The cash earned from a revenue-generating transaction is a (positive) asset, and so to balance it you need that revenue amount to be a negative somewhere in the books. This just affects the accounting financial statements (like the income statement or balance sheet; in the books both numbers would be entered as positive amounts in a transaction known as a "journal entry" in which you report the increase to one account and the offsetting decrease to another account.
Credit = money flowing out of an account or creating a new liability = decreases asset and expense accounts but increases liability and revenue accounts
Debit = money flowing into an account or reducing a liability = increases assets and expense accounts but decreases liability and revenue accounts
This website that you call nonsensical was a huge help to me when starting to learn about accounting systems. And I have spent several years of my life working on a (special purpose, non-generalist) accounting system.
The important thing is just a shift of perspective. It is just a different way of viewing the same system. The website doesn't contradict the things you write about at all.
Saying "double entry book-keeping is basically a checksum" and "a transaction of two entries is basically an edge in a graph" is just two views into the same model. Like working in real space vs Fourier domain. You can move between the representations but they represent the same underlying thing.
It seems your main gripe is the use of negative numbers instead of credit/debit.
I feel certain that if negative numbers where around when double entry book-keeping was first done then credit/debit would not have been invented.
Once you "grok" it, viewing an income account balance as a negative number and an expense account as a positive number makes so much sense.
Yes, using credit/debit instead of +/- is more normal, and if you use +/- you have to be prepared to translate at the UI later to terms more commonly used in accounting. But is is the same thing. You can just translate between them.
The article is not nonsensical at all. But perhaps it should have explained the regular use of debit/credit instead of negative numbers more explicitly.
The words used doesn't change the concepts though.