One of the deepest assumptions marbled within the canon of classical economic thought is best described as a sort of rationalist fantasy that posits that the material world is knowable and mappable, which produces working models and the attendant data which allow us to predict and manipulate the real world. Practical economics then would be an application of this data to craft an efficient and just system for distributing energy in a human system.
Now of course, theoretically, everything could be knowable on an empirical basis - well, maybe, ignoring inherent limitations in our rational systems, and assuming that these limitations can be overcome through finer working models and data sets - but there arises the practical question of whether this theoretical mastery is possible given available energy and an imperfect world in which a large portion of this usable energy is wasted.
Barring a sudden activation threshold in which the secrets of the universe suddenly come pouring forth into our skulls, we are left with precipitous gaps in our knowledge, which shift and expand or contract depending on our confidence and social harmonies. Rational systems do indeed illuminate portions of reality, tracing those deep dark contours with illuminating clusters of interrelating symbols, but there stubbornly remains those gaps, which upon greater scrutiny, drop far below into depths we could only begin to fathom.
The just woman, the just man has great respect for these gaps, and wields her or his rationality with cautious awe and humility. The well-intentioned yet foolhardy woman or man wields rationality with a passion and an intensity, plunging headlong into the abyss with an irreversible direction, to be great, yet to be swallowed by the relentless churn of history. The evil woman, the evil man wields rationality as a weapon, using it to buttress her or his selfish aims, obstructing the yawning gaps that threaten to make a mockery of her or his position.
In the way of the latter example, mainstream economics seeks to legitimate plunder and collective self-destruction through the veneer of a surface rationality. So for example, you see plastic cups, forks, spoons, bags, and whatever else you can imagine in plastic form just about everywhere. Lavish federal subsidies, collective values, economies of scale, human cooperation, and other factors make it so that plastics are incredibly cheap, and the resulting economic incentives make it inevitable that every self-interested business uses them to keep costs low.
Now the value of these plastic products are calculated using all of the familiar economic models, tools which are the product of an underlying set of rational assumptions. But what if we incorporated everything we actually knew about the true collective costs of plastic, and there are costs well beyond which we don't understand yet.
Plastics can persist for quite some time in oceans and even longer in landfills, and there are tons upon tons upon tons of plastics floating in the oceans, photodegrading and breaking down into polymers and other toxic components, which can act as sponges to soak up even more toxic chemicals in the ocean, making their way into the food chain through phytoplankton and other organisms. And then well, you have mass stretches of mysterious dead ocean, and of record species die-offs, phenomena which themselves can have complex causes behind them. And then of course we are eating the seafood, or we are eating land animals which eat the seafood.
So we would have to make the collective decision that we don't want toxic-covered polymers in our food chain, and we would have to calculate the collective medical costs, economic loss in food and even biodiversity, and the clean-up procedures that these effects would require - which is probably impossible, but there are always approximations and mitigations to be done. Calculating these externalities into the costs of plastic - mainstream economics is notoriously contemptuous of externalities - one could imagine the actual prices soaring, with every last business abandoning the material as a result.
The same can be said of fossil fuels. We still use them because they contain so much energy, and because our society is configured for them, they are cheaper than everything else - well, for now. Take into account externalities, and future costs associated with expelling carbon, and well, hah! I could imagine the price soaring to somewhere around infinity, as a joke anyways.
Now, we've slowly become more conscious of these things collectively for the last four decades, but the information and the implications of the information have been suppressed by powerful economic actors every step of the way.
The rational systems then are artificially truncated into limited representations that deliberately produce and legitimate a very selective state of affairs that benefits a small group of powerful people, while the gaps are completely ignored or even demonized. The whole thing is just absolutely incredible. Incomprehensible.
Fundamental behavior patterns seem the most difficult things to change.
