Final answer:
An individual typically cannot claim a tax deduction for paying someone else's expenses. The tax system has principles like the benefit and ability-to-pay principles to ensure fairness and proportionality in tax contributions.
Step-by-step explanation:
It is generally true that an individual cannot claim a tax deduction for the payment of the expenses of another individual. The tax code typically requires that one can only deduct expenses that are directly related to their own income-generating activities, and not for the benefit of others unless specifically allowed by tax law (e.g., some exceptions like claiming dependents). The benefit principle and ability-to-pay principle underpin many tax systems worldwide. The benefit principle argues that taxes should be paid in proportion to the benefits received, while the ability-to-pay principle suggests that taxes should be levied based on an individual's capacity to pay, making it fairer for those with higher incomes to pay more in taxes than those with lower incomes.