Nothing could be more foolish, further from the letter and spirit of Spinoza's writing than to proclaim that a given proposition is the most important. Spinoza's thought is in the movement and relation of the different propositions, axioms, and definitions, not this or that proposition. His thought is systematic, not aphoristic, which is why his thought does not lend itself to tweets, memes, or bumperstickers. However, there is one particular proposition which remains a personal favorite. It is Proposition One of Part Four, "Nothing positive which a false idea has is removed by the presence of the true insofar as it is true." This idea always seemed important to me in that it offers a corrective to the spontaneous philosophy of philosophers, the idea that true ideas and well reasoned arguments have a force in and of themselves.
As Spinoza clarifies in its demonstration, false ideas that have a powerful imaginary or affective component cannot simply be countered by the truth. Spinoza's example here is our experience of the sun, which continues to rise and set each day even though we know the truth about its position and Earth's movement. Imagination is irreducible to knowledge. What is more important is that fact that the true insofar as it is true is also limited in response to intense affects. Fears and hopes, sadness and joy, are not countered by a dispassionate consideration of the facts, but are dispelled only by other intense affects. Only an affect can determine an affect, an imagination an imagination. Every parent knows this, this is why protective teddy bears are more effective protection for monsters under the bed than discussions as to why monsters do not exist.
The concept of fake news is obviously a spurious one. Anyone with any understanding of propaganda, or memory of the New York Times' coverage of the buildup to the Iraq war, knows how incoherent the idea of a division between fake and real news is. It perhaps only makes sense as an attempt for facebook and other services to boost their brand, offering a news filter. If there is any basis for the concept, something beyond the handwringing of the pundit class and possible new revenue streams for the vectoral class, it is in foregrounding the imaginary and affective basis of people's relation with news.
A quick glimpse at a site like Literary Unbelievable, a website dedicated to documenting the times that The Onion or Clickhole's articles were shared as truth illustrates the fact that confusion is at its highest when the story in question corresponds with some pre-existing idea or sentiment about the government or politicians. There is a reason why that story about a massive abortion complex or Obama's secret kid have been shared more than others, they feed into established ideologies about the government as well as racist ideologies about black men. "Inadequate and confused ideas follow with the same necessity as adequate, or clear and distinct ideas" (EIIP36). Fake news, or clickbait, is better understood as news which places the affect and imaginary dimension first, it plays into what people want to believe or already believe, the story does not even need to be read before it is shared. This is something that Trump understood when he recently called CNN fake news, his point was simple, "you say things that my followers do not want to hear." He understood better than most the empty and polemical nature of the concept.
Many of the creators of fake news have no political or ideological orientation, they are simply looking for clicks, for traffic, but they understand more than the opponents of fake news that traffic is driven by desire, by hopes and fears. This is why the various fantasies opposed to fake news, fantasies of fact checking, of restoring truth and authority, are ill-fated at best, if not completely complicit in the existing order of things. As Frédéric Lordon has argued, post-truth politics has its corollary the idea of post-political truths, of facts outside of ideologies and narratives.
Clearly there is room for basic awareness of media and how it works in combating "fake news," but the real combat, the real focus, is not in the limited efficacy of the "true insofar as it is true," but in creating counter narratives and imaginations. The real opposition to myths of murderous immigrants, rampant abortions, and cheating recipients of welfare is not to be found simply in recounting the facts of hard working immigrants, the various services Planned Parenthood offers aside from abortion, etc., but in constructing new hopes to counter these fears. This is something that the reigning ideology of the reasonable center is unwilling and unable to do, but must be a part of any real opposition.