There are plenty of other explanations aside from geography alone that explain inequality too.
In all fairness, many of these explanations take the form "once the inequality started, this is what perpetuated and amplified it."
When you see a cabin crushed under a gigantic avalanche, and someone asks "why," well, there must have been a first sliding stone, or a sound that set the snow to sliding. It is a valid thing to say "I'm not interested in that first cause," but it is at least a valid question for
someone to make inquiries about, even if Diamond isn't the guy I'd go to for all my answers.
As a final note: If we take the testimony of Titu Cusi Yupanqui as reliable than doesn't it reinforce Diamond's point on there being a major difference in capability that can be blamed on literacy? Whether societal literacy and its lack thereof gave an advantage in preparation before the battle and the ransom negotiations or the bizarre decisions that led to Atahuallpa meet the Spanish band without overwhelming numbers doesn't matter. The key point is that Atahuallpa made a fatal miscalculation at some point. It is simply a far greater miscalculation if we treat Titu Cusi Yupanqui's testimony as superior to that of the Spanish.
Hypotheses:
Atahualpa may have figured that no small group of adventurers with no outside backing would have the nerve. He may have underestimated how effective Pizarro's men would be in an all-out attack, thinking that even unarmed, his entourage would be able to beat a fighting retreat in case of treachery. He may have thought he'd be able to sniff out treachery more easily than he, in fact, could; he wouldn't be the first monarch to overestimate himself.
Imagine the obvious counterfactual diamond's claim suggests:
The indigenous people of central Mexico and South America have invented writing and have literacy rates comparable to the Spanish.
Does this forestall pizzaro? Does it thwart his treachery?
Frankly, I don't see it.
Spanish oceangoing ships mean that on a strategic scale, their expeditionary forces can literally outrun the hypothetical messengers Whether the messengers are carrying written letters or just memorized impressions.
Those'd be some pretty slow messengers.
Roughly ten years elapsed between Cortez's invasion of the Aztec Empire and Pizarro's invasion of the Inca Empire.
I would not dispute the idea that Titu Cusi Yupanqui has unique insight into the functioning of the Incan court and the intentions of the Inca than the Spanish. My point is that this does not matter as the only issue at dispute here is whether the Inca expedition led by Atahualpa was a military force numbering in the tens of thousands as the Spanish wrote or a small unarmed court as Titu Cusi Yupanqui wrote.
You're going to look a little silly here, because the answer is, as others noted, "both." Atahualpa brought an army, but he went into the town with only his entourage because he'd been invited to a parley. The army was still camped outside the town.
You probably shouldn't be quipping about a source you haven't read and only heard described secondhand and saying "obviously someone is lying." That's the kind of statement you don't stake out until you're sure what the texts say.
One side must be lying in order to make their faction look good. I find it more credible that it is Titu Cusi Yupanqui given the aforementioned problems with the idea of a ruler of a nation of millions travel to meet a band of foreign soldiers without an overwhelming military force.
[squints]
Really?
I mean, you think about that, but you
don't think about the part where an Inca emperor might look insecure and tense if he brings a huge guard force of heavily armed soldiers along to a negotiation, when all known convention (including that of the Spanish!) holds that he shouldn't have to, and that his large unarmed procession of loyal followers should be quite enough?
But it doesn't. That's my point in the Mameluke example. Reading would not have helped the Inca because the Inca didn't have any books on the Spaniards. There were few prior interactions and Pizarro was a unique personality. Do you think reading about Albanians would have protected the Mamelukes from Muhammad Ali? Probably not.
In fairness, Atahualpa might have benefited from knowing that a similar expedition led by the literal second cousin of the guy he was talking to had just busted up the Aztec Empire...
by betraying and murdering its emperor. He might have at least viewed the idea of walking up to Pizarro on terrain of Pizarro's choosing without a sizeable armed escort with a livelier sense of caution.
If he already knew that, his decisions do seem rather unwise.
See, the thing is, this is giving Diamond too much credit.
You assume he explored a bunch of different options and settled on literacy. This, frankly, does not appear to be true. See my previous post where I note the simple thought-experiment of assuming a counterfactual. It does not take a deep dive into history to conclude that literacy is not a "primary determinant" here. It just requires some critical examination of the premise.
The thing that you may not be aware of is that Diamond is not a trained historian. He is a geographer by trade, and previously also studied physiology and ecology. Thus why a large part of his argument centers on things like the spread of crops/domesticated animals and large scale geological barriers - these are the things he has actual expertise in and are familiar to him.
When he brings up literacy as an explanation for historic events, he is speaking as a layman, a non-expert. And this choice of explanation appears to be more grounded in western chauvinism than well-considered historical inquiry.
Especially since he does not read and seems unfamiliar with the languages in which the primary sources wrote and spoke. Usually, one of the prerequisites of being a historian is the ability to directly read primary source documents. Roman historians are supposed to know Latin and Greek. Historians of medieval Germany should know medieval German. Historians of China should read Chinese, not just read
about Chinese or read Chinese in translation.
And historians of the conquest of the Inca Empire who are trying to make detailed analyses of specific historical events or battlefields... should damn well at least know how to read
Spanish, an easy language to learn in America and widely agreed to be one of the easiest to learn in general!