Direct contact? No. Indirect contact? Yes. Not just through the movement of people, but interaction through air, animal life, weather, and and other factors. People make the assumption that if humanity isn't interacting with different factions of the world then nothing could possible match that fact. The problem is that the world is a complex system, the slightest variation in the number of ants around the Great Lakes would effect Europe in unforeseeable ways within months. The interactions between life forms on our world and their effect on their environments is something that is scarcely understood. Its not butterflies for the sake of butterflies, it is likely to be gone because the effects of removing Confucius throws every event that would succeed his arrival into doubt, even if they were only fifty years in the future a couple thousand miles away.
Yeah, I know and understand the concept, its just not very helpful. Widespread, diffuse, indirect and unquantifiable changes? Basically you can either hit a randomize button, ignore them, or give up on speculation entirely. Sometimes I enjoy the first option, but I am willing to excuse the second for the sake of a coherant discussion. The third option I have no time for.
As for whether or not another dharmic religion would take Buddhism's place is inherently irrelevant. The fact of the matter would be that it is impossible to know or predict how said religions would evolve. And no, it does not stand to reason that it would be similar to OTL in its formation and in its execution through centuries of time while experiencing completely different stimuli in the form of civilization and so forth. Even if Buddhism could be butterflynet secured for several centuries it is almost impossible to believe that it would have remotely similar influence on the outside world.
If we went back in a time machine and killed Confucius in his cradle, sure. But it doesn't really matter for a speculative discussion, and it offers no insights.
We have some choices.
A) Declare ceteris paribus, ignore indirect butterfly effects and assume Buddhism rises anyway.
B) Assume indirect butterfly effects change the details, but assume the general social and cultural conditions that led to Buddhism in OTL lead to a roughly analogous dharmic faith that has a roughly equal effect.
C) Same as above, but adjust for taste. Have it more or less successful or widespread.
D) Look at the social and cultural environment and the existing philosophical and religious mileau and use this to construct another dharmic faith (or several) that replace Buddhism due to the raging butterfly winds. An admirable effort, but doesn't add much to a discussion about Confucius-less-ness.
E) Throw our hands in the air and declare it all too difficult and forget about it. Not my favorite option.
I never made an assumption like that of any kind, however many of those philosophical schools came about in reaction to Confucianism. Either directly because of the butterflies or directly because the philosophers who founded the various schools of thought specifically mentioned Master Kong in their essays.
This is true, particularly in the case of Mohism. Still, my point stands, other philosophical schools will arise anyway, and they will probably share some characteristics with OTL schools.
I never said nothing could take its place, I actually hinted that another Confucian-like ethic could arise stating that what Confucius did, while immensely important, was simply provided a uniform structure for the many different practices in the past. Assuming that another ideology would take its place is a safe bet as there has never been a people that has not had an ideology (even if their ideology is that there is no ideology

). Speculating as to what it would be, apart from a possible Confucian analog, inherently impossible without essentially making it up. Could we assume that a Legalistic Philosophy/Doctrine could arise? Sure. Hell, its basis for government and execution while predating many similar ideas was hardly unique. Others could arise to fill that void. Could we assume that Agrarianism could once again form its utopic message? Sure. We can equally assume that it will remain marginalized because of the nobility or it will be altered to fit into what the nobility wants. Could Mohism and his idea of universal love take form in a similar fashion? Sure. There are a few, but not many, people that make similar ideas in other cultures.
We can't know for sure, because there's no right answer. We can try to make educated guesses, though, based on what we know about the body of thought that existed at the time.
The point is, by saying something similar could take its place that doesn't mean it was likely or even realistic. It just seems like attempting to direct butterflies rather than seeing what would actually happen. Sure, every single one of the hundred schools of thought could form similar to the way they did in OTL, but under different names and founders, without Confucius; and that Buddhism would form exactly the way it did in OTL and spread to China in a similar fashion resulting in the same blending of thought, custom, and ethic. Its all very possible. But its all very unrealistic. There's a reason why I hate early changes like this one.
That's a reason why I love them, they leave so much scope for huge changes in trajectory. An element of creativity and winging it is unavoidable. What is your definition of "unrealistic" in this sense?
Never made that assumption. Rather I was pointing to all of the Confucian achievements directly or indirectly and how they helped forge what we call China from the Han onward, and removing Confucius would rob history of this. I would say that others would say that assumption would be based on Taoism and Buddhism's ideology and how it relates to science.
That was someone earlier up in the thread I think. It's hard to characterise this situation as robbing China of tradition, as thats a value-loaded way of describing it. It might be better, it might be worse. More likely, there are a multitude of different ways China can develop sans Confucius some better and some worse.
That said, I have never seen Confucianism described as advancing human knowledge and science. Confucius himself said "I invent nothing", after all. What advantages it might possess in encouraging scholarship and learning for learnings sake seems to be taken away by a generally conservative mindset and tendency to use brainpower on purely metaphysical or moral quandries.
It's also worth making the point that Daoism helped advance science in many ways. Mixing various chemicals in the search for an elixer of immortality led to gunpowder and the classification of many plants and animals. But sure about Buddhism and science one way or the other.
I do not believe that Legalism and Buddhism would mesh well together. Certainly less so than Confucianism and Buddhism or Taoism and Buddhism. The basis for this is the harshness of Legalism and the apparent lack of many similarities that are found in either Confucianism or Taoism. Don't get me wrong, Confucianism and Taoism clash with Buddhism, and in many ways contradict one another, but with Legalism we have an entirely different animal. About the only thing it shares is its desire for harmony, but how it achieves this is radically different.
One could see Legalism and Buddhism complementing each other as secular and private faiths, like Confucianism and Daoism did OTL. I think they're fundamentally focused on different things, so there's not as much of a clash as you think. In OTL, Buddhist conceptions of right-ruling kings had an influence on many Chinese nobles, and this didn't conflict with their use of Legalist ideas and structures.
One could say that without Confucianism a legalistic doctrine would evolve with many Confucian ideologies in order to make it more acceptable to the gentry and more compatible with other faiths and ethics, but this just seems like wishful thinking to me.
Not really, considering that many aspects of Confucianism predated Confucius, and as Confucianism developed it took on Legalistic elements. It seems to me to be the most conservative prediction, and as such I find it a bit boring.