Talyra

For me, at least from a thematic point of view, it was a humorous throwaway comment designed to illustrate the dangers of pure rationality used alone. That, instead of inviting contradiction, suggests to me that his master plan is flawed. Brilliant, and right on many/all points so far, but as I've said above, not infallible. The way BS is exploring principles and values tells me that the separation of intellect and compassion is vital for understanding the thematic goals of the series. I don't think we should be reading Taravangian as perfect at all. I think this is a clue pointing to the opposite conclusion.

There is also the suggestion that when he's in one of his more brilliant states, his ideas flow fast and at times incoherently. When writing the Diagram he digresses, thinks out loud (well, on desk drawers) and babbles. Why could we not suppose that he simply doesn't have time to think all of his ideas through? It seems to me that his intelligence comes with commensurate pride, so he may not consider the weaknesses of a throwaway idea which only tangentially relates to his real goal. (And Moogle, thanks for the thought, even if the button doesn't work!)

Is there some significance to the widespread anxiety Shin and Taravangian seem to have at the reappearance of the Radiants? We know that the appearance of the Heralds and KR is an omen for a Desolation, but could there be some kind of causal effect as well? Taravangian is specifially concerned about the exploration of the Nahel bond: "One danger in deploying such a potent weapon will be the potential encouragement of those exploring the Nahel bond. Care must be taken to avoid placing these subjects in situations of powerful stress unless you accept consequences of their potential Investiture. - From the Diagram, Floorboard 27: paragraph 6" I suspect from this that the investiture itself may act as a trigger for something, perhaps an escalation of events to come. It could just be that the Radiants are unpredictable elements and throw off Taravangian's predictions, but it seems suspicious to me. If that were the case - if widespread investiture were damaging or endangering the world somehow, then sacrificing the spren could definitely have a higher purpose.

Despite Moogle's objections, I think this does raise a question - what happens if Taravangian has a day of pure compassion? While it's possible that he might just be shut away in his room, if he encounters another immense statistical anomaly reversed, it could potentially have implications for his plot. I feel that it's foreshadowed, and his safeguards are not necessarily infallible...

Yeah, it does make sense to me. It's never stated that he's infallible, just incredibly smart and equally limited. I think zandi makes a really good point that politics (responding to people's natures as they are) and social engineering (attempting to change those natures) are very different spheres, and one is demonstrably harder than the other.

Perhaps the key is that the Diagram was written in his most brilliant moment, whereas the suggestion you're referring to was merely on a very good day. We know he loses more and more of his compassion, but I wonder if at his highest point, the intelligence compensates for the lack of insight provided by compassion. He asked for the capacity to save the world, not to fashion the perfect society. Perhaps that's a part of the catch? His brilliance just isn't practical when applied to other matters. However he does fail to anticipate Kaladin's actions right at the end - it's another instance where he fails to grasp the human element.