He suspected it might be a law of Erfworld, but there was not enough evidence.
Strengths: Curiosity, Generosity, Inventiveness, Building Scientific Instruments, Stylish Jackets
Weaknesses: Loneliness, Focus, Courage of Convictions
First Appearance: TBFGK 140
Isaac is a rarity among the casters of the Magic Kingdom, not content with debating and arguing over theories and hypotheses on the nature of magic and Erf, but actively working to discern reliable and consistent facts. So far, this has led to the creation of a number of devices to aid thinkamancers in better accessing nodes of amplification or attuning to the frequencies of certain G-String vibrations (all of which resemble children's playground equipment from our world).
Should he ever link up with a Carnymancer, they will create devices capable of automatically switching Thinkamancers between nodes at precisely calibrated frequencies to achieve Thinkamancy that, while not as versatile, will actually rival the Arkendish in power (like a Ferris Wheel or a Roller Coaster).
Real World References
His name coupled with his tendencies as a natural philosopher are a reference to Isaac Newton. Some of his suspicions about the laws of Erfworld include that there is "A counter-force for every force, a reaction to every action. Opposite, and perhaps equal." which is one way of specifying the real world (Isaac Newton's) First Law of Physics.
His appearance is a reference to Carl Sagan.
His desire for the Arkendish as a tool of observation may also be a reference the use of radio telescopes in astronomy.
Both Carl Sagan and Isaac Newton were teachers, and one of the titles for the person in charge of a school is Headmaster.
Before he tells Parson his name, Parson calls him Mr.Rogers which he does kind of resemble, but he is younger looking.