Some 80 or so years prior to Caesar's assassination, a consul fomented a mob to kill a Tribune (G. Gracchus) who was pushing hard for land reforms. Historians often cite this as laying the foundation for the Roman revolution because it normalized violence as a political tool. It was followed by proscriptions and the Catilinarian conspiracy in 63 BCE.

What if Octavius never traveled to Hispania? Caesar may well have still adopted his nephew in order to make him his beneficiary. What would have happened if there were no Octavius? Possibly Marcus Antonius would have consolidated power.

Would we have no transistors today if Shockley hadn't worked at Bell Labs?

I guess my viewpoint strongly biases me towards seeing continuity and underlying processes. For every tipping point, there was a pre-existing process; for every process an event you can treat as a "handle".

What's your take on Catiline? I have just enough classical education to be a little dangerous, but my understanding is that he's sort of seen as a would-be Julius Caesar who showed up at the wrong time; Cicero was horrified by them both, but his conservative faction eventually lost so much power in the Senate that Caesar succeeded where Catiline failed.

I can see that. Both Caesar and Catiline sought power through extra-constitutional means. Caesar surely took notes (and Cicero thought Caesar even secretly supported Catiline). They were all in the senate together under Cicero's consulship, after all.

They were all hyper-ambitious patricians. The conservatives (optimates -- the best) regarded the populares (the faction Caesar aligned himself with) as people willing to threaten the order of the state by pandering to the masses. This is what Catiline did, and Caesar too. This was the basic threat that the Gracchi brothers appeared to present in agitating for land reform and something that underscored Caesar's political agenda (he had to find land for his loyal veterans).

I agree with your main point here but anyone who thinks violence as a political tool needed normalizing should not be listened to.

They're saying violence being normalized was a necessary step for the foundation of the empire. There's no moral judgment there, saying they should not be listened to would not change what happened.

This assumes he wouldn't impress Cesar later on a different occasion or that it was the first time he was trying to convince his mother to let him go.

Yes, I agree. However, life is short, and you have to take advantage of every opportunity you can to impress someone like Julius Caesar. There's no guarantee that you'll have another opportunity to spend time with such a busy and powerful man, even if he is your great uncle.

I just want to go in a small tangent here, but I imagine that if Cesar knew he was going to die and had to adopt someone to continue his rule, he probably wouldn't pick his sickly nephew with no experience, no matter how bright he might be. So I think it's very likely that Cesar put him in his will since he is a blood relative and didn't really expected to die soon anyways, but didn't mean to have him as his sole heir forever.

That's a good point. Did Julius not have a mental disorder which caused him to lack fear? It's a good for Octavian that he got close to his great uncle while he could.

I've wondered if this isn't a "just so" story told by Octavius. Caesar just may not have had a lot of good choices, so posthumously adopted Octavius and made him his beneficiary, in which case it could have happened regardless of the trip (though it might be hard to make that case stick).