P. 107. _For Pythagoras always proclaimed, that nothing admirable pertaining to the Gods or divine dogmas, should be disbelieved._ This in the Protreptics forms the fourth symbol, and is thus explained by Iamblichus:—“This dogma sufficiently venerates and unfolds the transcendency of the Gods, affording us a viaticum, and recalling to our memory that we ought not to estimate divine power from our judgment. But it is likely that some things should appear difficult and impossible to us, in consequence of our corporeal subsistence, and from our being conversant with generation and corruption; from our having a momentary existence; from being subject to a variety of diseases; from the smallness of our habitation; from our gravitating tendency to the middle; from our somnolency, indigence and repletion; from our want of counsel and our imbecility; from the impediments of our soul, and a variety of other circumstances, although our nature possesses many illustrious prerogatives. At the same time however we perfectly fall short of the Gods, and neither possess the same power with them, nor equal virtue. This symbol therefore in a particular manner introduces the knowledge of the Gods, as beings who are able to effect all things. On this account it exhorts us to disbelieve nothing concerning the Gods. It also adds, nor about divine dogmas; viz. those belonging to the Pythagoric philosophy. For these being secured by disciplines and scientific theory, are alone true and free from falsehood, being corroborated by all-various demonstration, accompanied with necessity. The same symbol, also, is capable of exhorting us to the science concerning the Gods: for it urges us to acquire a science of that kind, through which we shall be in no respect deficient in things asserted about the Gods. It is also able to exhort the same things concerning divine dogmas, and a disciplinative progression. For disciplines alone give eyes to, and produce light about, all things, in him who intends to consider and survey them. For from the participation of disciplines, one thing before all others is effected, viz. a belief in the nature, essence, and power of the Gods, and also in those Pythagoric dogmas, which appear to be prodigious to such as have not been introduced to, and are uninitiated in, disciplines; So that the precept _disbelieve not_ is equivalent to _participate_ and _acquire_ those things through which you will not disbelieve; that is to say, acquire disciplines and scientific demonstrations.” P. 88. _After this manner therefore it is said that music was discovered by Pythagoras._ The following particulars relative to music are added for the purpose of elucidating what is said about it in this chapter. “Take two brazen chords, such as are used in harps; for those chords which are made from the intestines of sheep are for the most part either false or obnoxious to the change of the air,