- A robot may not injure a human being or, through inaction, allow a human being to come to harm.
- A robot must obey any orders given to it by human beings, except where such orders would conflict with the First Law.
- A robot must protect its own existence as long as such protection does not conflict with the First or Second Law.
Howard and Raj have accused Sheldon of being a robot based on the fact that he has never broken the First and Third Laws. Interestingly, they skipped the discussion of the Second Law, even though it may have ended their deliberations since Sheldon does not have a history of following orders. ("The Fuzzy Boots Corollary")