The trouble with negative income tax, or at least the simplest models is, that you have to be very careful with the models. I once tried to calculate an admitte

The trouble with negative income tax, or at least the simplest models is, that you have to be very careful with the models. I once tried to calculate an admittedly very simple model and the results were a rather absurdly high tax already at rather low incomes. A slightly larger parameter space then produced a model of taxation with extrema. Plus there are a lot of very good reasons for tax breaks (for example screen readers for the blind). So while I fully agree that a well engineered tax system would be a lot simpler than what we have now, I am not sure if a basic income should just be dealt with by taxation.