Eudaimonia and Makariotēs in the Letter to Menoeceus

Quote from Godfrey

Epicurus advised the study of nature though I don't know that he went so far as to say his philosophy is the study of nature

I see where you're going. I find think we'll find a definitive "my philosophy is the study of nature" but PD11/12 comes close (emphasis added )

PD11/12. If we had never been molested by alarms at celestial and atmospheric phenomena, nor by the misgiving that death somehow affects us, nor by neglect of the proper limits of pains and desires, we should have had no need to study natural science (φυσιολογίας physiologias). It would be impossible to banish fear on matters of the highest importance, if a man did not know the nature of the whole universe, but lived in dread of what the legends tell us. Hence without the study of nature (φυσιολογίας) there was no enjoyment of unmixed pleasures.

Don : But isn’t the standard tripartite division physics, ethics and canon? What am I missing?

Quote from Pacatus

Don : But isn’t the standard tripartite division physics, ethics and canon? What am I missing?

Touché. Good point. And physics is the study of nature. However, physics was a fundamental component of philosophy for everyone. From Diogenes Laertius' Lives 1:18:

Philosophy has three parts, physics, ethics, and dialectic or logic. Physics is the part concerned with the universe and all that it contains; ethics that concerned with life and all that has to do with us; while the processes of reasoning employed by both form the province of dialectic. Physics flourished down to the time of Archelaus; ethics, as we have said, started with Socrates; while dialectic goes as far back as Zeno of Elea. In ethics there have been ten schools: the Academic, the Cyrenaic, the Elian, the Megarian, the Cynic, the Eretrian, the Dialectic, the Peripatetic, the Stoic, and the Epicurean.

I firmly agree that Epicurus sees the study of nature as fundamental, but other schools would probably have said something similar. That said, Epicurus also wrote to Herodotus that:

"Hence, since such a course is of service to all who take up natural science (φυσιολογίᾳ), I, who devote to the subject my continuous energy and reap the calm enjoyment of a life like this, have prepared for you just such an epitome and manual of the doctrines as a whole