His research areas are logic and artificial intelligence, focussing primarily on the use of logic to model human-like planning, reasoning, and problem solving. Of special interest is the modelling of social phenomena and social intelligence with the aim of creating computer systems that can interact intelligently with humans and other computer systems. The application areas of interest are e.g. computer-controlled characters in computer games, intelligent personal assistants in mobile phones, and mobile robots. Thomas has developed and taught a wide range of highly praised courses in mathematics, computer science and artificial intelligence, having received the "teacher of the year" award at DTU in 2006. He is also a book reviews editor for the Springer Journal Studia Logica, and scientific advisor for the Science & Cocktails initiative.