Let's say an employee earns $500 before tax and has to pay 20% income tax. The employee will take home $400 and $100 will go to the taxman. If the employer paid that $100 income tax instead of the employee and paid the employee $400 it would make no difference to the employer, the employee or the taxman. Income tax is therefore an indirect business tax on human productivity.

So, why do employers pass this tax burden to employees? The answer to that is simple. When businesses replace human labour with automation, they no longer have to pay that tax either indirect or directly and therefore the government lose out of the tax revenue and society is poorer because of it.

Income tax is an indirect business tax on human productivity but what is required is a tax on the productivity of both humans and machines so that the government doesn't lose tax revenue as businesses automate. That can be achieved with a direct productivity tax on businesses that would replace various taxes that businesses already pay (such as income tax).

The productivity tax would be progressive like income tax with the business' productivity determining its tax band and rate. Productivity can easily be restated as the amount of money you earn from every $1 you spent, therefore, those who make the most money from every $1 spent would have the highest tax rates.

This is how you tax automation to pay for a UBI which will be essential as society automtes.