is unable to provide insights to other topics for the sake that they are simply needed or wanted—he has to write what is in his head. Like his brother Don, he is characteristically stubborn and obsessive ("one part exuberance, two parts obsession"), especially when it comes to work, but he's rather naïve when it comes to human behavior. The latter often interferes with his FBI work and, thus, is the cause of much distress for him at times. He is extremely talented in chess, as it requires both his father and brother to play against him and a distraction to defeat him. Charlie also has a vast understanding of theoretical physics, often assisting Larry with his multi-dimensional supergravity theory and papers on gravity waves, and biology, extending to knowledge of ciliate protozoa and the spread of infectious diseases. While brilliant in some areas, he is lacking in others. Dr. Fleinhardt has stated that it is a good thing he went into applied mathematics as opposed to engineering, as machines malfunction in his presence, though he was able to take apart and rebuild his father's cell phone to analyze its GPS transceiver. He is apparently a bad speller (e.g., he misspells "anomaly" and "conceited") and does not know the meaning of "defenestration" (for which Larry chastises him stating that the idealization is to be a Renaissance man and that even math and physics majors had to have a course on English). Thus, his father likes playing Scrabble with him. Charlie is a rationalist. He is skeptical of UFOs, psychic ability, and gematria—all considered to be pseudosciences. He also does not like illusions. He, however, is also fairly open-minded in terms of faith and religion. Evolution over the series The episode "Uncertainty Principle" is significant for the backstory it gives on the familial relationships, particularly Charlie's difficulty in dealing with his mother's death from cancer. While it's unclear how Don reacted, Charlie spent the last three months of his mother's life isolated in the garage, incessantly working on one of the Millennium Prize Problems, specifically P vs NP; it's a point of contention between the brothers. Also, Charlie doesn't think Don understood what he went through during their school years, especially how he was treated as "Don's brainiac little brother" by his peers in high school, and how he often left him to his own resources as a child, though he was