The fact that he is talking in 3rd person shows he's trying to view himself objectively and be rational, offering a pensive element to his character, also suggesting he's quite analytical.
Faustus begins by considering Astronomy but rejects it, despite admitting to enjoying the work of Aristotle, he asks himself 'Is to dispute well logic's cheifest end?' Is it just to win arguments? Is the miracle just being able to argue? He dismisses this subject, confident he can argue well.
He then considers medicine. He refers to Galen, an influential Greek physician. The biggest authority of medicine in the middle ages, yet he rejects being a doctor, saying you can achieve so much but at the end of the day you cannot bring some one back to life, you are still only a man. 'Yet art thou still but Faustus'.
He then moves on to Law, referring to the work of Justinian, another founder of thought associated with the profession. He rejects this though, as he seems to think it is nothing worth doing. 'His study fits a mercenary drudge'. So he rejects law for being servile.
(NOTE AT THIS POINT THAT IT SEEMS HE IS BEING VERY NEGATIVE, YET HE IS TALKING IN 3RD PERSON, SUGGESTING HE IS BEING RATIONAL ABOUT HIS DECISION AND WITHOUT PREJUDICE)
He then moves on to consider religion, using this time the influential name 'Jerome', the one who translated the bible into Latin and put it all together.
He goes on to say that if we say we haven't sinned, we are deceiving ourselves therefore we die, however if we sin, we die, there is an inevitability. He rejects the study of God, believing it is below him, and almost mocks it when he says 'che sera sera'.
He then turns to magic. 'He picks up a book of magic'.
'Of power, of honour, of omnipotence' - This links to expectations of our gothic protagonist. The power hungry and high status elements which also tie in with the sadistic features.
He wants everything at his command, 'All things that move between the quiet poles Shall be at my command'.
(ALSO NOTE THAT FAUSTUS IS ON STAGE, IN FRONT OF AN AUDIENCE, AND A RELIGIOUS ONE FOR THAT TIME.)
so it seems he is being massively Blasphemous, Marlow is depicting Faustus as a bad character to the audience.