How can government know how much you owe them when they don't know all your tax deductibles?

By knowing all your tax deductibles?

For which you have to file them first, for which you need to know the specific rules applying, for which people are using an expert, or AI.

	▲	orthoxerox 10 minutes ago \| parent [-]
		No, the other party should file them. Charities can file the lists of donors etc.