Fairly broad term for ideas influenced by KarlMarx
Quora Answer : Was Karl Marx a genius even if he was wrong on the big picture?
Marx's great originality comes from putting together two bodies of work which were in their own fields widely known and (sometimes) respected but which no-one had either tried or succeeded in putting together before.
One was classical economics. (At that time, represented by Adam Smith, David Ricardo etc.) The other was the philosophical transcendental idealism coming from Georg Wilhelm Friedrich Hegel and his followers.
Most of what people complain about being wrong in Marx, actually comes from one of these sources. The Labour Theory of Value was mainstream within the economics of the time. The labelling of the economic classes comes from that economics. The descriptions of how capitalism worked, were largely just elaborations within that tradition. At the same time, the idea of history as having a directionality or teleology, which could be diagnosed and predicted, comes from Hegel. The idea that human nature is not fixed, but historically relative, comes from Hegel. The idea that history advances through a dialectic logic which is embodied in actual violent struggles between peoples comes from Hegel.
Marx's originality is to bring these two bodies of thought together. To transpose what Hegel saw as a "clash of civilizations" between different ethnic tribes led by great men (Hegel was a big fan of Prussia as the culmination of the rise of civilization) down to the concrete reality of how people got fed and stuff got made. To make the everyday grubby business of earning a living into an epic struggle of ideas.
You should remember that Marx's background is upper middle class. His wife was an aristocrat. The politics of the end of the 18th and first half of the 19th century was driven by the conflict between the conservative aristocracy and the newly emerging, more liberal, industrial capitalist. In a sense, Marx is rebelling against his aristocratic (and philosophically idealist) roots and siding with the industrial liberals in saying "THIS STUFF MATTERS". Economics, work, production, factories. These are what's really going on. What really makes the world tick. Not Napoleon or which branch of the Hohenzollern family is in power.
Again, remember that Marx is a German living in London. In modern network-theory language he has "betweenness centrality", he's trying to span the "structural hole" between the pragmatic British empiricism that underlies Adam Smith, and the transcendental idealism that came to dominate German philosophy. He's trying to square the circle and create a grand unified philosophical theory of everything by bringing the two together.
Finally, Marx is a political agitator. Marx didn't invent working class resentment at their ghastly working conditions. He didn't invent the anger. Or radical politics. Or the outbreaks of violent insurgency. Sometimes people seem to blame Marx for the very existence of working class uprising. But obviously there were riots and massacres, and revolutions and communists long before he came on the scene. But Marx hung out with activists and shared their idealism. And when he retired to think and write, he tried to offer these revolutionaries a principled basis to work on. By slotting their struggle into his elaborately built system.
So really Marx is the bringing together of three things : Hegel's idealism and philosophy of history as struggle; British classical economics with its analysis of the anatomy and dynamics of the emerging capitalist system; and working class agitation. Finding a way to make such disparate ideas fit together is a monumental act of intellectual creativity. And pretty unique in intellectual history.
While you have to admire that ... doesn't "genius" kind of require you to be, at least somewhat, right? Cleverly putting together a lot of wrong things seems like it shouldn't be valid. Otherwise we're going to have to start talking about all kinds of system-building conspiracy theorists as "geniuses" too.
I don't think there's much shame for Marx that some of his sources were later over-turned. People make a lot of fuss about the Labour Theory of Value. But that's what many people really assumed at the time and it's not Marx's fault that they revised their theory later. I personally think that Marx can survive deprecating the LTV (Phil Jones (He / Him)'s answer to Why are there still so many Marxists if Marx's labour theory of value has been discredited?)
Hegel is more contentious. The whole Hegelian framework is very contrived. It's neat in theory but doesn't stand up to much empirical inspection. Even to the extent you can tie it to real events, those are very Eurocentric and a quick contemplation of Chinese or Indian or African history would surely knock it over. Marx's variant tries to resolve some obvious problems ... but that still raises the question : why stick so closely to Hegel's big picture if you're going to overturn all the small details? I may be wrong, because I haven't read anything by Marx justifying his position here, but it feels that it is just a lack of imagination and critical thinking on his part to accept the Hegelian framework so absolutely.
My guess is that he may also have held on to it because he wanted some kind of theory of the dynamics of long term change. And Hegel's was really the only game in town. And he wanted some reason to give the working class revolutionaries hope that they could succeed, and his twist on Hegel gave them that.
Then there's the moral question. Isn't it just plain "evil" to be advocating violent uprising that are going to hurt and kill people?
Well yes. But remember that the 19th century Europeans were a lot less squeamish about such things than we are in the 21st century. Today we have international law, and human rights and medicine sans frontiers and a tonne of other institutions and moral beliefs that give wars a high barrier of moral justification. Now I don't want to defend us too much ... we are utterly venal, fighting too many, disgusting wars. But right up to and through the 19th century, Europeans fought wars and killed each other over all kinds of trivial crap. Most people in the upper aristocratic classes thought fighting and killing other people was a highly respectable and admirable occupation, that war was easily justified and glorious. And the right-wing Hegelians, from Hegel himself to Francis Fukayama and Samuel Huntington and the US Neocons, similarly believed (and still believe) that civilization was advanced by the most civilized tribe fighting and killing and taking over the territory of the lesser. Marx didn't particularly add to that. He just asserted that the downtrodden working class could be the "tribe" capable of rising up and producing the next level of civilization.
Nevertheless, I don't think we can call Marx a genius if he basically did nothing except put together a bunch of bad ideas.
For him to be valued, I think we need to find some true and original ideas. I think we can.
Now, I'm not 100% certain of this. People who know the literature and intellectual climate of Marx's times might be able to point out precursors who said these. But it seems to me we can find three ideas that are
and fall out of Marx's system building
Firstly, the idea that economics is prior to politics. Of course, there's feedback ... political decisions and events and culture shape the economic system. But the economic structure is the geology which underlies and gives form to everything else. And its tectonic movements, shape historical movements. I think Marx was the first person to really emphasize this. Especially the idea that the mindset or zeitgeist itself is formed by the economic relations in society.
Even people who hate Marx, tend to hate him because they think that his economic prescriptions will lead to bad political and social effects. So even they are agreeing that the economic infrastructure exerts a strong push on everything else.
Secondly, the idea of the "class war". Most political theories from the 18th century, and adopted by Conservatives and even classical Liberals, tend to see the different actors in society rather like organs in a body. They have common interest in the overall success of the whole body (say, the nation) and the ideal is that they collaborate harmoniously. People shouldn't be upset at their position in the pecking order.
Marx, on the other hand, offers dynamic equilibrium. A kind of ecosystem where, like different species, the different classes are jostling for position, fighting over economic rent, and any apparent stability is not "harmony", but just the current balance of powers.
For the mediaevals, a peasants uprising was an affront to God's will and the natural order. For Hobbes, it was at least contrary to self-interest of the peasant who ultimately benefited from Leviathan's order. Right-wingers of all stripes, from the most religious to the most atheist, the most authoritarian to the most liberal (even self-professed progressives), still assume these views. Whereas Marx's tradition valorizes the uprising. Like the lion eating the antelope (or perhaps the elephant defensively gorging the lion with its tusks) the fighting is a legitimate part of shaping society. The classes ARE antagonistic. And will continue to fight to hold their own until the economic system that pits them against each other is finally replaced.
Finally, the idea that accumulation makes Capitalism an unstable and "auto-destructive" economic system. I've written more about this on Phil Jones (He / Him)'s answer to Are the ideas of Karl Marx still relevant in the information age? so won't go into detail here. Marx makes the case that Capitalism contains the seeds of its own destruction. This I think is perhaps the most crucial belief that divides those really in the Marxist tradition (who may well have jettisoned and revised many other Marxist shibboleths) from everyone else. Including the liberals and progressives from the "third-way" left, who have made accommodation with neo-liberal economics and who believe that Capitalism is eternal (at least until the asteroid strikes).
Marx's tradition insists that even if you eradicated EVERY Marxist, even if Marx's name and entire theory were to be forgotten. Even if every opponent of, and constraint on, and criticism of, Capitalism disappeared tomorrow. Then this would only accelerate the end of Capitalism. It's not Marxists or socialists or progressives who will tear down Capitalism. It's that Capitalism simply isn't a sustainable system. At some point, the accumulation will have syphoned so much of the wealth and resources up into the hands of so few people, that something will have to give. Marx hoped and wrote that breakage would herald the coming of socialism. We may not be so optimistic. Perhaps it just comes in the form of a violent uprising that leads nowhere but more of the same. Or the election of authoritarian demagogues. Or rising crime rates that make civil society unbearable and impossible. Or the literal destruction of the bodies or psyches of the exploited through depression and malnutrition. Or perhaps the services provided by the environmental commons give out and it becomes harder to find clean water or air or good farmland or prevent the ill effects of pollution hurting your people. However the rupture comes ... it will come; because no system where the positive feedback loops outweigh the negative feedback loops can remain intact forever. And, as Marx noted, the positive feedback loops of accumulation, the extra opportunities and power of the investor class to grab more of the economic rent from the world's economic activity, have nothing to counterbalance them within pure Capitalism.
tl;dr : Marx is a brilliantly creative "system builder" who brings together at least two, perhaps three, fundamentally different systems of thought and finds a unified theory to combine them. For some people, that is enough to recognise his "genius". For others, that system needs to contain some actual original true insights to be worthy of the title. I'd suggest that three insights : the primacy of economics over "geist", the class war, and the ultimate unsustainability of capitalism are good candidates for this kind of insight and why Marx is still relevant today, even if we lose many other of his ideas.
Quora Answer : If there is continuing widening of the rich/poor divide, high unemployment, and a collapse of the major developed economies, will Marxism make a comeback?
Personally, ten years ago I used to think Marxism was outdated and irrelevant to our post-industrial information age. Today I think it's fairly essential to understanding what the hell's actually going on in the world.