What would you say to Marx if he was alive today?

I turn on the flashlight

That's cyber, motherfucker. You want me to set it to kill instead of stun?

Labour is consciously transforming one thing into another. Our species-being or human nature is being able to envision the tool before we make it, and that process was understood to be uniquely human in Marx's time while we now halfway assign it to other intelligent animals.

Marx's underlying idea, his most important in my opinion because it's the root of ecology, is metabolism. Metabolism is the universal natural function of transforming one thing into another. The squirrel, bee, and river all exist through their metabolic functions and the dialectical relationship that organism forms with its environment. They all need a certain amount of A to produce B for the consumption of the higher trophic level. What environmentalism is missing is a hard materialist analysis of the value of that work. We need all of those components of an ecosystem to have a sense of metabolic stability in order for society to exist on top of it, and introducing a metabolic rift between what we demand of nature and what it can produce is the original sin which capitalism sends into overdrive.

My big criticism of Marx as a Marxist is that he predated ecology by a century but all of those ideas are scattered throughout other works. Engels went on to write The Dialectics of Nature which is flawed, but Marx never got around to the thing that would have given us a theoretical answer to climate change 40 years or so before the first observations of it. Marx was the direct inspiration for the bionomics that became ecology, but if he had given a really thorough dissection of how an ecosystem functions economically then I think he could have skipped ahead to something approximating Carson's Silent Spring in the 1960s. That'd be the work I could give to anyone as the most relevant thing to them.