Comment by Kliment

Ideally, the funds don't primarily come from other people's income, they come from corporate wealth and income (currently severely undertaxed), taxes on natural resource use (currently severely undertaxed), taxes on things we don't want like carbon emissions and other pollution (currently severely undertaxed) taxes on nonrenewable limited resources like radio spectrum usage or land usage (currently not taxed at all or nowhere near proportional to value most places), and direct wealth generation from nation-level investments (sovereign funds, resource funds). The "taxes come from people" is a common way to paint UBI as a self-defeating cycle of redistribution, but that's not how it is. Human income is a dropping fraction of total income, and human wealth is a dropping fraction of total wealth.