They always felt that they were in the presence of unknown incalculable powers, and that subtle dangers lurked in human achievements and gains.
Horace has taken this feeling as the motif of a criticism on man's inventive powers.

A voyage of Virgil suggests the reflection that his friend's life would not be exposed to hazards on the high seas if the art of navigation had never been discovered--if man had submissively respected the limits imposed by nature.

But man is audacious: Nequiquam deus abscidit Prudens oceano dissociabili Terras.
In vain a wise god sever'd lands By the dissociating sea.
Daedalus violated the air, as Hercules invaded hell.

The discovery of fire put us in possession of a forbidden secret.

Is this unnatural conquest of nature safe or wise?
Nil mortalibus ardui est: Man finds no feat too hard or high; Heaven is not safe from man's desire.
Our rash designs move Jove to ire, He dares not lay his thunder by.
The thought of this ode [Footnote: i.