Should robots pay tax?

Should robots pay tax? It sounds like a daft idea, but increasingly many people are putting this idea forward. The basic idea is that if a robot replaces a person doing a job, for example a taxi driver, then just as the taxi driver would pay tax so should the robot. This tax revenue would go to pay for social services. A recent exponent of this idea is Bill Gates who explains his reasoning in a recent interview for Quartz.