The one minute market utilitarian case for a basic income:
The free market is the greatest generator of wealth ever devised. Money is the most effective means of socially producing utility, as it allows each individual to obtain whatever needs and wants they subjectively require. However, one dollar in the hands of a poorer person produces greater utility than a dollar in the hands of a richer person, because the richer person can fulfill more of their more important needs and wants with the rest of their money than the poorer person can. So the transfer of money from a richer person to a poorer person increases overall utility. The government is incompetent at running people's lives or regulating the economy, but the one thing it can do effectively is mail out checks. A basic income is most effective means of transferring money from the richer to the poorer with the least government interference and the least work disincentive. The natural limit on the amount of the basic income is the point where the work disincentive from the required taxes reduces wealth the point where the basic income would have to be reduced.