This controversy led Descartes to post two open letters against his enemies. The first is entitled Notes on a Program posted in 1642 in which Descartes refutes the theses of his recently estranged disciple, Henricus Regius, a professor of medicine at Utrecht. These Notes were intended not only to refute what Descartes understood to be Regius’ false theses but also to distance himself from his former disciple, who had started a ruckus at Utrecht by making unorthodox claims about the nature of human beings. The second is a long attack directed at the rector of Utrecht, Gisbertus Voetius in the Open Letter to Voetius posted in 1643. This was in response to a pamphlet anonymously circulated by some of Voetius’ friends at the University of Leiden further attacking Descartes’ philosophy. Descartes’ Open Letter led Voetius to have him summoned before the council of Utrecht, who threatened him with expulsion and the public burning of his books. Descartes, however, was able to flee to the Hague and convince the Prince of Orange to intervene on his behalf.
The account leaves room for doubt regarding the nature and extent of Aristotle's empiricism. In particular, it seems that Aristotle considers sense-perception only as a vehicle for knowledge through intuition. He restricted his investigations in natural history to their natural settings,  such as at the Pyrrha lagoon,  now called Kalloni , at Lesbos . Aristotle and Theophrastus together formulated the new science of biology,  inductively, case by case, for two years before Aristotle was called to tutor Alexander . Aristotle performed no modern-style experiments in the form in which they appear in today's physics and chemistry laboratories.  Induction is not afforded the status of scientific reasoning, and so it is left to intuition to provide a solid foundation for Aristotle's science. With that said, Aristotle brings us somewhat closer an empirical science than his predecessors.