Objectivist philosopher Harry Binswanger hates Popper. He replied to a question about Popper on his HBL forum, 2011-03-22:
HB: Popper has fooled you. He's one of the most notorious skeptics and positivists in 20th Century philosophy. He is the author of the “falsifiability” doctrine, which is an updated version of the positivist Verification Principle. It holds that (vs. the older positivists) nothing can be verified, we can hold onto to the distinction between what's scientific and what's meaningless by reference to what can be falsified. Here are a couple of juicy quotes from Popper's main work, Objective Knowledge (the term “Objective” here means what Kant meant by it—collective subjectivism—not what we mean by it).
This [realist] doctrine founders in my opinion on the problems of induction and of universals. For we can utter no scientific statement that does not go far beyond what can be known with certainty 'on the basis of immediate experience'. (This fact may be referred to as the 'transcendence inherent in any description'.) Every description uses universal names (or symbols, or ideas); every statement has the character of a theory, of a hypothesis. The statement, 'Here is a glass of water' cannot be verified by any observational experience. The reason is that the universals which appear in it cannot be correlated with any specific sense-experience. (An 'immediate experience' is only once 'immediately given': it is unique.) . . . Universals cannot be reduced to classes of experiences . . . (pp. 94-95)
HB: So, all statements are subjective, because statements use concepts and concepts are not logically derivable from perception.
Popper wasn't a positivist. Popper refuted postivism. But anyway, let's focus on the quote.
That quote is not from Objective Knowledge. It's from a different book, The Logic of Scientific Discovery. It's also on different page numbers. Has Binswanger read any Popper or does he just copy/paste quotes from the internet that someone else missourced?
Not reading Popper would explain why Binswanger doesn't know the context of the quote. He used square brackets to insert the word "realist" as a paraphrase. He presents Popper as attacking a realist doctrine. That's false.
The doctrine which Popper believes founders is not realism. Here is some preceding text describing the doctrine Popper opposes:
Science is merely an attempt to classify and describe this perceptual knowledge, these immediate experience whose truth we cannot doubt;
Popper is criticizing a doctrine which treats percepts as infallible and never bothers with concepts because it believes that thinking cannot add anything useful to sense perception.
Popper's main point here is that strong forms of empiricism (like positivism) are mistaken. Our knowledge is not merely a collection of observations and their deductive consequences. Rather, men do more than perceive: they think. By using our minds we go beyond 'immediate experience'.
Popper's position here is actually in agreement Objectivism. Objectivism, too, says we need to conceptual thinking about our observations.
Binswanger didn't care about his quoting error – both getting the book and content wrong – and didn't allow further discussion on his forum. His last word was:
Objectivism holds that perception is infallible and that all science is, ultimately, the unpacking of what's implicit in perception. There's no question that Popper is completely wrong and is the philosophical father of people like Feyerabend. On the latter, see the article, "The Anti-Philosophy of Science," by James G. Lennox (U. Pittsburgh), in The Objectivist Forum.
Popper criticized people who don't unpack perception. The lack of unpacking was part of what he was criticized. The view he was criticizing believes, in Popper's words and italics, "[science] is the systematic presentation of our immediate convictions". What Binswanger says here is actually still compatible with Popper.
Binswanger's comment on infallible perception is misleading. Objectivism holds that error is an attribute of conceptual thought. People make errors. Rocks don't make errors, they just follow their nature or identity (or in other words, follow the laws of physics). Similarly, eyes are outside the human mind. Seen as tools, eyes are like microscopes or cameras. They just obey the laws of physics. If a person has blurry vision because he isn't wearing glasses, that isn't an error, that is what eyes with that physical form see in those circumstances. The error would be if the person thought reality was blurry when it's not. I don't recall Rand saying that herself, but I've talked with a bunch of Objectivists about it and that's my understanding of the matter. That view is reasonable, true IMO, compatible with CR, and not infallibilist.
Smearing Popper with Feyerabend's ideas is also unfair. The issue should be whether CR is true. Here's what Popper had to say:
As far as my former pupil Feyerabend is concerned, I cannot recall any writing of mine in which I took notice of any writing of his.
That's from p 1069 of The Philosophy of Karl Popper, Volume 2, edited by Paul Arthur Schilpp.