On Feyerabend’s view of an immanent reason, the problem with rationalism is that it is not rational enough, because it ignores or impoverishes both our humanity and the natural world. Disconnected from the constraints imposed by the real, rationalism taken to the extreme would attribute reality only to its own constructions. Feyerabend is not a “constructivist” – he does not agree that everything is a construction of the subject (or of one of its avatars, such as “reason” or “society”) nor even of some common basis such as genetics, as the case of astronomy (for example, our knowledge of the fixed stars) shows that our knowledge of the real “goes beyond similarity” with us, and that we need not have anything in common with the objects of our knowledge:
“At some point it ceases to make sense for me. I also think about and try to figure out what fixed stars have in common with me. So one understands lots of things. But you cannot say: the explanation is in a similar genetic code. The whole of astronomy is another example which goes beyond similarity”.
It is this alterity and heterogeneity of the real which makes Feyerabend hostile to the idea of its status as a construction, which he gently makes fun of when Jung brings up Maturana and Varela:
“J: They explain subjectivity in a very reasonable manner. They say that everything is a construction of the subject.
F: You are my construction? That means: if I stopped constructing you, you wouldn’t be here anymore?” (p163).
He finds that such views impose too much unity on the heterogeneous material of the universe. I do not need to construct an object, or to be constructed myself in a similar way to the object, in order to know it. In fact, knowledge implies the primacy of dissimilarity, alterity, and multiplicity. This is the ontological counterpart to Feyerabend’s methodological pluralism, which he presents as a simple fact of the practice of science:
“Just look at the history of the sciences. Compare what some physicists have said at one time and at another time, in some [personal] letters. You find all sorts of methods. And this is not a philosophical position. This is just a statement of fact” (p161).
For Feyerabend we are not free to construct reality however we like, some approaches simply fail to be supported by the real. He is not a naive relativist who thinks that all ideas and all points of view are equally good:
“This is relativism because the type of reality encountered depends on the approach taken. However, it differs from the philosophical doctrine by admitting failure: not every approach succeeds” (AGAINST METHOD, Postscript on Relativism).
We can see this confrontation with failure and with the illusory nature of some of our constructions in Feyerabend’s dialogue with von Weizsäcker. Defending an abstract methodological pluralism, Feyerabend, made to consider the real developments of quantum theoretical research, saw that his systematic account was a phantasm unsupported by the real:
“I realized that what I was talking about was just a dream” (p162).
One of the limits to our rational constructions, he came to see, is the richness and heterogeneity of the raw material of the world:
“Excellent arguments don’t count when you want to deal with something which is as rich as nature or other human beings” (p162).
Deleuze agrees that in our research and in our lives we are dealing with a rich heterogeneous material, and he signposts this with a philosophical word and concept: “multiplicity”. what we “deal with” according to Deleuze is always a group of multiplicities, along with various operations of rationalisation and of administration, of participating in the multiplicities or relating to them on the same plane, or of simplifying, unifying, and organising these multiplicities in the name of some transcendence such as Reason or the Subject.
Feyerabend does not like such philosophical terms as “subjectivity” which assume a division that does not exist in reality:
“I wouldn’t say that, because “subjectivity” is already a philosophical expression which assumes a division between something objective and something subjective. I would never assume that, because these things freely interpenetrate” (p161).
Given this free interpenetration of elements across abstract divisions, Feyerabend is acutely aware of the ambiguity of our words, our concepts, and our perceptions, and of the richness of the material that we participate in and try to deal with. Encountering von Weizsäcker’s arguments allowed him to see the richness of the material, how “there are so many little steps being made” (p162). The historical development of quantum theory appeared to him as a rich and heterogeneous assemblage of multiplicities that could not be organised into the simple narratives proposed by “methodology freaks” and by rational reconstructors. Weizsäcker’s arguments caused Feyerabend to abandon the rational attitude (really, as we have seen, the transcendent attitude) and to adopt a freer, more open, more complex attitude - the “participative” attitude (or, in deleuzese, the immanent attitude). We can call this attitude “pluralism”, provided that we understand this aright as participative pluralism (or immanent pluralism) neither proposing nor making use of standards that do not themselves vary with the progression of the research that they judge.
Thus a variety of approaches exist and are necessary because of the nature of reality itself, which imposes strict limits on our constructions. Which constructions work, and which fail, are not a matter of a priori constraints that guarantee the applicability or not of our conceptual schemes, but is an empirical question. This is why Feyerabend towards the end preferred to call his position “ontological relativism” to emphasise that pluralism was both required by Being and subject to its constraints. Feyerabend is fond of reminding us that not all constructions can succeed, not all forms of life can flourish. But more of them than we think can and do succeed and flourish. In this way, we see that both Feyerabend’s positive suggestions and his negative criticisms stem from his views on reality, are grounded in his ontology.