Gonzalo Munévar is a professor in the School of Humanities, Social Sciences and Communication at Lawrence Technological University in Southfield, Michigan, and a former student of the philosopher of science Paul K. Feyerabend. He is the author of several books, which are linked to in the body of the interview, and also a keen writer of fiction that his teacher enjoyed (see his The Master of Fate, for example). I was fortunate enough to be able to ask him about Feyerabend - both the man, his approach and his ideas - as well as some of Professor Munévar's own thinking.
- Interviewed by Paul Newall (2005)
PN: How did you first become interested in Feyerabend’s work?
GM: I was writing a Master's thesis in the philosophy of mind when I ran across his papers on what later came to be called "eliminative materialism", the view of which the Churchlands are the main exponents today. Those papers made me realize that to do philosophy of mind properly one had to place it in the context of philosophy of science. When I went to Berkeley for my doctorate and became his student, it was only natural to read his work in the philosophy of science. He was so mesmerizing, one wanted to read his papers. That was four years before the publication of Against Method.
PN: What did you learn from your time as Feyerabend’s student?
GM: You have to understand that at the graduate level Feyerabend never taught his own work, at least not directly. Everyone in his seminar was supposed to give a presentation, on a topic of the student’s choosing, and he criticized every presentation in a very forceful way. If his views came in at all, they did so in the discussion, in the argumentation going back and forth. It was not in the style of most graduate courses and seminars, but rather in the style of Socrates, except that it did not have the endearing but self-serving statements Socrates used to make. Feyerabend was practically without ego, at least in his graduate seminar. After I presented what I thought was a very original idea in that seminar, I tried to impress another professor with it. The professor told me Feyerabend had already published it some years previously. It was in one of the few papers of Feyerabend I had not read. But sure enough, the idea was in it. I asked him why he had not said anything to me. He said he had forgotten all about it, so when he heard me explain it, he thought the idea was mine and new. I wish I had learned his modesty, but I am afraid I’ve never managed to be that good of a person.
In his undergraduate courses he did lecture, and in his lectures he did more formally exposed students to his views, but he never pushed those views even then. What I did learn from Feyerabend was to be true to my own philosophical inclinations. I guess that is why I gravitated towards him so easily: he let me be myself. I think by the time I finished my first seminar with him, it was understood that he would be directing my dissertation, even though we never explicitly discussed his involvement.
I also learned from him that it was possible to hold the intuitions (or prejudices) that I had about science and philosophy without being a fool. I went into philosophy because I thought it was a mess that needed straightening out. I had all the impulses of an analytic philosopher but felt that analytic philosophy was a dead end. So it was wonderful to meet such an extraordinarily gifted man who thought along the same lines (well, roughly) and encouraged me.
PN: Discussing Feyerabend's "Anything Goes" argument, you have written that "it should be an embarrassment to the profession that many reviews were completely unable to see the structure of this simple reductio". Why do you think philosophers of science then and since have been so quick to misunderstand Feyerabend?
GM: Not just philosophers of science. Epistemologists are even worse. The reason, I suspect, is that analytic philosophy is a very narrow way of thinking, and it is hard to manoeuvre mentally under such constraints. But there is really no excuse. Feyerabend's arguments were very simple and straightforward reductio ad absurdum arguments: you use reasoning to tie together what the philosophers' standards tell them is evidence, and then you point out obvious conclusions that completely destroy their empiricist views. But in offering a reductio, you need not accept the evidence or the reasoning yourself. Otherwise, atheists who offer reductio arguments against the existence of God would have to (sincerely?) accept that God exists, since they advance such existence as a premise for the sake of their argument. It's amazing that philosophers who constantly make this point, to their students for example, could not see that they themselves were committing the mistake.
PN: Why do you think Against Method and Science in a Free Society in particular were so misunderstood?
GM: Against Method attacked practically every major intuition about scientific method that philosophers had had for three hundred years. He just had to be wrong. People wanted desperately for him to be wrong. And he used the history of science to make his points. This presented two additional problems. The first is that the epistemology of science was supposed to be about how science ought to be, not about how it is. The second was that philosophy of science was also presumed to be about the "logic" and "grammar" of scientific concepts. Feyerabend showed that the latter approach was simply irrelevant to understanding science. As for the first, he showed not merely that scientists violated the methods thought up by philosophers (and by scientists like Newton in their philosophical moods) but that they actually had to violate such methods if progress (or what we know consider progress) was to result. So even the philosophers that thought history irrelevant were now looking at the history of science and building alliances with "solid" historians, for they thought that Feyerabend's account of history just had to be wrong. What eventually happened, of course, is that they came up with "devastating" objections that turned out to be little more than paraphrases of Feyerabend's own work.
By the time Feyerabend came out with Science in a Free Society, he was already a pariah and many philosophers refused to take the book seriously. The curious thing is that Feyerabend later took back just about every new thesis that he advanced in that book. That was the one work of his he came close to disowning. In particular, he took back the extreme relativism expressed in it (particularly on p. 70, for which it seems that I am to blame, if you pay attention to his footnote) and the thesis that all traditions should be equal before society, and he scaled back the most important corollary of that thesis, namely the separation of science and state.
PN: Describing Feyerabend, you have written that he "[was] probably the most interesting person I have ever met […] but his devastating criticism [wa]s the sort one would wish on one's worst enemy, or oneself when taking seriously the notion that criticism is at the heart of progress and improvement of ideas. The man question[ed] everything; even obvious claims c[a]me up for challenge and sometimes ridicule." Did you ever have any reservations about his approach? Do you think it contributed to the hostile reception he received in some quarters?
GM: Some people never forgave his exposing their weak arguments for what they were. And the fact that he did it with a great sense of humor made them feel also ridiculed – they took it personally. I know that his mode of criticism contributed to the hostile reception he received in some quarters. He once showed me a letter from a famous philosopher whose book he had just criticized in print. The letter was one ad hominem insult after another. It also contained an announcement to the effect that Feyerabend was now in the writer's "enemies' list." On the other hand, he liked to bring down people he thought were pompous. Some friends of his told me that he had gone too far a few times. I wasn't there those times. When I was there, I really relished his manner. He openly made fun of me often. But I made fun of him just as often.
There was an additional motivation on his part. Just as an idea discredited for two thousand years – the idea that the earth moves – can revolutionize science, the ideas from other cultures also have the potential to contribute to the progress of science. This implies that we should treat with respect cultures that differ from the Western culture, no only in spite of the admiration we feel for the Western advances made possible by science, but precisely because that respect will help maintain the climate of pluralism that is vital for the progress of our celebrated science (I explain this point below).
Therefore, the lack of respect towards the traditions of ordinary people – the "vulgar," as philosophers used to say – and especially the lack of respect prompted by an empiricist conception of science can lead to a very damaging intellectual arrogance.
Consider for a moment that until rather recently a person could end up in prison for practicing acupuncture (medical fraud); that in the name of "development" millions of women in the Third World were advised to stop breast-feeding their children and use powder milk instead (which of course they mixed with contaminated water on more than one occasion); and that in the presumably most advanced country in the world a high percentage of people are so obese they can hardly walk, thanks to a "scientific" diet – a diet officially sanctioned by the state – that forbids eggs (to which the human body is adapted) and emphasized, still emphasizes, refined carbohydrates (to which the human body is not adapted, which causes all sorts of physiological problems, obesity amongst them).
Feyerabend detected that sort of arrogance in the contempt that many intellectuals feel towards ordinary people, their beliefs and their traditional customs. That is why he made fun of intellectuals, shattered their "reason", and called them "fanatics" and "criminals" for creating suffering and misery in the world by imposing their abstract "truths" on everyone else. His reaction may seem exaggerated, but we must understand it in the proper context. In the first place, if a tradition has served a society well and has allowed its members to adapt well to their environment, we have no right to impose our truth on them, no matter how scientific and confirmed it may appear to be. In the second place, many of the intellectuals' abstractions, even if named "truth" or "justice", are the result of bad reasoning (which he demonstrated with many examples), while the valuable ones are so only within a limited practical context. His last (and posthumous) book, Conquest of Abundance, deals with this issue of abstraction in great detail.
PN: You have written (of Feyerabend) that "philosophy of science can well afford bold thinkers who are prepared to defend implausible ideas against all comers". What do you think motivated Feyerabend to "provide a service" in this fashion and why is it beneficial to the philosophy of science?
GM: He didn't do it to provide a service. He did it because he was too intelligent not to see the flaws, too honest not to point them out, and too imaginative not to conjure up alternative approaches.
My response to the Mill question below is relevant here too.
PN: How would you describe the relevance of Feyerabend’s thinking today and his legacy for the future?
GM: The big philosophical problem about science was that the scientific method worked but we could not prove so: classical skepticism, Popper's efforts notwithstanding. Feyerabend came in and cleaned house: the so-called "scientific method" did not work; it actually got in the way of scientific progress (as defined by the empiricists themselves). I think this is a finding of the greatest importance, although not his only contribution. Philosophy cannot – should not – be the same after that, even though professional philosophers will keep on doing pretty much the same things for as long as they can get away with it. I am reminded of Romero's film "The Dawn of the Dead", in which the zombies go to the shopping mall to walk around and window-shop as they used to do when they were alive. Analytic philosophy no longer makes sense, in great part thanks to Feyerabend, but there you have it: a philosophy for zombies. But the zombies are still in charge, so who knows how Feyerabend’s legacy will play in the years to come.
Philosophy of science also suffered, before Kuhn and Feyerabend, because it was a pseudo-mathematical and irrelevant game. With a few exceptions (e.g., Popper) it was practically unreadable. That was the way the philosophers of science liked it: it made them feel superior. They did "science" too, not just some mushy humanities. Philosophy of science should have had something to say to scientists, but the scientists could not make any sense of it. And if you did go through the effort, the rewards were far too small. In that respect things have improved quite a bit. It is now possible to find whole articles in philosophy of science written almost completely in English, or Spanish, or some other honest-to-goodness language.
In any event, his main legacy is a more humane and exciting understanding of science that ties philosophy to the practice of science, as I will explain in my response to the next question. It is also a legacy of respect for other people and other times.
PN: What would you consider Feyerabend’s most important contribution and where do you think he erred?
GM: Somebody wrote in Nature that Feyerabend was the worst enemy of science. But, on the contrary, Feyerabend showed how complex and humane science is and ought to be. Of his many contributions, perhaps the most important is that there is no method or rule that can capture science completely. The most excellent idea about the nature of science has to allow exceptions. When we look at the history of science, we discover not only that the great scientists violated the methods proposed by the empiricists, but that they had to violate them, otherwise they would not have secured the great successes through which we know them today.
Until the publication of the work by Feyerabend and Kuhn, it had been generally supposed that scientific rationality consisted in behaving in accordance with certain methodological rules. And science was the shining example of human rationality. Those methodological rules were inductive, as envisioned by Newton. The philosophical problem was that even though we "knew" that such scientific method produced knowledge, we could not prove it. Karl Popper argued that the problem came from thinking erroneously that induction was the method of science. We just needed to realize that science was based instead on the method of trial and error. But Feyerabend's analysis of the history of science demonstrated that adherence to all proposed methods, from Francis Bacon's to Popper's, would impede the progress of science. To progress, then, science needs to act against method from time to time.
The reason is very simple. All varieties of empiricism assume that experience determines the worth of our scientific ideas. This assumption is presumably justified because through experience scientists learn directly what is written on the book of nature. For example, if all observers see a stone fall vertically, the vertical motion of the stone is an immediate or direct truth given by observation – an immediate truth with which our most profound hypotheses about the world must agree. If a hypothesis implies that the stone does not fall vertically, our observations, our experience will then refute it. Unfortunately for empiricism, as Feyerabend reminds us, the Copernican hypothesis claims that the earth rotates on its axis to give us the day-night cycle, and this claim is refuted by the vertical fall of the stone.
This was one of the main objections against Copernicus that Galileo confronted in 1632. If we let go of stone from a tall tower, we see it fall vertically, close to the tower, and touch ground next to the base of the tower. Let us suppose now that the earth rotates. If so, when the stone begins to fall, the tower continues moving as the earth rotates, and therefore (if we choose the direction conveniently) the tower is going to move a considerable distance before the stone hits the ground. The only way the stone can hit the ground next to the base of the tower is by moving in a parabola; but we all see it fall straight down instead. It is clear, then, that the earth cannot rotate.
What did Galileo say when confronted with such a clear refutation of Copernicus? Galileo refused to accept the verdict of experience. If the earth does not move, he said, the stone will surely fall straight down. But if the earth does rotate, the stone would have to fall in a parabola. The reason we see it fall vertically is that its motion has two components: one in common with the earth, the tower, and the observer; the other towards the center of the earth. But the observer does not notice the motions it shares (today, for example, we don't see the other passengers in our jet plane fly at 900 kilometers per hour). This is why it seems to the observer that the stone falls vertically.
What motion one accepts depends on the theory one favors. Insisting that the stone falls vertically presupposes that the earth does not move. That is, Copernicus' opponents assume the truth of what is in question – does the earth move or not? – when they declare the their experience is veridical (the stone does fall vertically). Their empiricist argument is no more than an instance of the fallacy of petitio principii [begging the question].
Feyerabend points out that the observer sees a phenomenon (the motion of the stone) and interprets it in a way that seems natural to him: the stone falls vertically. It is that natural interpretation of the phenomenon, but not the phenomenon itself, that contradicts the Copernican theory. Galileo dissolves the contradiction by offering a different way to interpret the phenomenon. Galileo gives us, then, a new empirical basis constituted by a theory of interpretation congenial to Copernicus' ideas.
These considerations do not imply that scientific hypotheses or theories always defeat the verdict of experience, but they do imply that such victories by theory are possible. This result implies in turn that all empiricist methodological rules must have exceptions. The reason is that such rules assign a higher priority to experience (over theory). We have seen, however, that the great scientific revolution would not have happened if Galileo had not violated such rules. Similar results can be expected in the majority of critical episodes in the history of science, as Feyerabend argues in his work. It bears emphasizing that it was not just a couple of hunches that allowed Galileo to take a short cut that led to the same findings that the patient use of method would have provided in the long run. Not at all. If method gives priority to experience, method would have forever closed the path to a point of view that could not be established without first defeating previously accepted experience. If, by developing a theory already refuted by experience, Galileo committed a sin against science and philosophy, we must then love not only the sinner but the sin.
Feyerabend rescued Galileo from the preposterous role of being the first and greatest hero of empiricism. By doing so, he allowed us to understand science very differently. In this contribution he did not err. He erred in his proposal that all traditions or ideologies should have equal standing. But eventually he realized that, as Marguerite von Brentano had argued, the Nazis and the Quakers would then have equal access to pursue their goals, even though one of the Nazis' main goals was to exterminate other cultures. He also acknowledged, though reluctantly, my criticism to the effect that a society has the obligation to teach its young the skills and the views they need to survive, and that in a world that depends on science that is what students will have to learn, not astrology or voodoo. He thus came to see that there were drastic limitations to his notion of the separation of science and society. So where he erred he changed his mind anyway. I think he also erred in his going away from relativism. Of course, the relativism he attacked in his later work was the caricature provided by analytic philosophers, namely that the truth, or the good, of an idea or action is relative to a culture or point of view. Relativism can be far more sophisticated than that. Nevertheless, given the range of problems he examined, it is remarkable how insightful he was.
PN: Feyerabend wrote often about Mill's famous essay On Liberty and how he had extended the arguments found in it. What was the extent of his debt to Mill in your opinion?
GM: Feyerabend points out that we are often unable to even discover important evidence against our favorite theories unless we consider seriously alternative theories that can propose and make sense of counter-evidence such as the compound motion of bodies in the case of the Copernican theory. Our science has, then, greater opportunities to progress if we accept a theoretical pluralism. This is the second important historical contribution made by Feyerabend, a contribution closely allied with his first. No matter how certain we may be of a theory, a scientist who fails to accept it and develops instead a different theory is doing science a favor. For as Feyerabend says, "We need a dream-world in order to discover the features of the real world we think we inhabit (and which may actually just be another dream-world)."
This second philosophical contribution of Feyerabend acts not only against Newton but also against the important tradition of Plato and Descartes, whose obsession it was to discover the correct path to unique truth. Century after century, generation after generation of skeptics sowed doubts about the path to truth suggested by this or that great philosopher. But Mill was the first important philosopher who rebelled against the goal itself. In his essay On Liberty, Mill argued that it does not favor society to force its members to accept the official point of view – no matter how certain it seems to be. By allowing the development of different points of view society profits, for if the official point of view is false, we gain the opportunity to replace with another that might be at least partially true. And if the official point of view turns out to be true anyway, comparing it with alternative points of view allow us to understand it better. Feyerabend's accomplishment in this area comes from extending Mill's philosophy to science. Science also profits by allowing the development of points of view different from the one that "agrees with the facts." And we find one of the best examples of how science profits precisely in the case of Galileo and his defense of the Copernican revolution.
Feyerabend's ironic sense of humor led him to proclaim anarchy in the philosophy of science and to suggest that "anything goes." But he never offered anarchy as a sort of anti-method method. Anarchy is the description that a traditional rationalist would give to the way science should be done according to Feyerabend, and particularly the description that rationalist would give of pluralism. It is that rationalist who finds it obvious that rationality consists in behaving in accordance with the rules of the method of empiricism. And it is that rationalist who recoils in horror at the "anything goes" attitude in science a la Feyerabend.
PN: How did Feyerabend influence your own work?
GM: He set the stage for the future development of philosophy. For example, if we could no longer say that science was rational in the traditional sense, could we still talk about science as a rational activity? My answer is "yes". A good deal of my early work developed a biological conception of science in which we could see that science was indeed a rational activity in a very straightforward ends-to-means conception of rationality. He first accepted my evolutionary relativism, but in his later work he argued against relativism on some very interesting grounds. I think he is wrong, but definitely worth replying to. He also pointed out to me a strong connection between Bohr's ideas and my biological approach to philosophy. This connection is becoming more and more important in my work. Another important influence is the notion that concepts and meanings are flexible and may change. We can see that in the history of the physical sciences and should expect it in our growing understanding of the mind as neuroscience advances (that is the main point of eliminative materialism). It also shows why analytic philosophy was doomed, since analytic philosophy relies on stable concepts so logic and argument may shine in all their glory. He was influenced by Wittgenstein in this last issue, but I think he goes well beyond Wittgenstein.
Incidentally, this is where the linguistic version of the infamous problem of incommensurability arises. Philosophers of science thought of explanation as logical derivation. And new theories explained their predecessors, which became special cases of the new theories. Science thus evolved by accretion. But, if we are strict about meanings, it seems that the meanings of scientific terms change when theories change. In that case, new theories cannot explain the old, for in the presumed derivation the meanings of some terms would vary from the premises to the conclusion. Philosophy of science then committed science to perennial equivocation. This was a big problem for philosophers, who tried to fix it by changing their theories of meaning. But Feyerabend pointed out that scientists should not lose any sleep over this issue, since they were very flexible and pragmatic about the meaning of their terms. I have argued that incommensurability is indeed a serious problem for empiricism, for it makes us realize that there is no common measure or standard by which to judge the worth of competing theories, as Galileo demonstrated. At any rate, "facts" do not provide such a standard, and this result is a dagger in the heart of empiricism. I have also argued that this problem is independent of theories of meaning.
Feyerabend's main influence on my work, beyond setting the stage for many of the problems that have concerned me, is his example of being honest and daring.
PN: What do you think is the relevance of the philosophy of science today? What are the main issues you are interested in?
GM: The field has become more relevant today, in spite of all the remarks made to the contrary by Feyerabend, and in great part because of his influence. One of reasons for the increased relevance is that Feyerabend and Kuhn showed us how important the practice of science is for philosophy. So many, particularly younger philosophers, even some who learned from their mentors that Feyerabend was a kook, now bring their philosophical energy to interesting controversies in the practice of science. Some of them have interesting points to make, and some times the scientists pay attention. This brings me to a second and related reason: we have done away with the silly formalist approach, at least in great part. So scientists can now read what philosophers say with some chance of understanding it. That allows them to respond to the philosophers. This in turn gives the philosophers the chance to say more pertinent things in the future.
I am not talking about a world-shattering movement here. But it is an improvement, and Feyerabend deserves a good part of the credit, in my opinion.
The journal Science recently compiled a list of 25 hard scientific questions, and I realized that about two thirds of them are questions that enter my own work in some way or another. Many of them are addressed at least briefly in my next book, The Dimming of Starlight: What is the universe made of? Can the laws of physics be unified? How does Earth's interior work? How and where did life on Earth arise? How far can we push chemical self-assembly? How hot will the greenhouse world be? And even: What can replace cheap oil and when? Some of the other questions I deal with in class and my take on them will be making its way into print slowly in the next few years: What is the biological basis of consciousness? Why do humans have so few genes? What determines species diversity? What genetic changes made us uniquely human? How are memories stored and retrieved? How did cooperative behavior evolve? What are the limits of conventional computing? Do deeper principles underlie quantum uncertainty and non-locality?
The reason these questions enter my work is that some of them have interesting philosophical consequences while in others there are philosophical comments worth making about the methodologies used by scientists to tackle them.
But of course you wanted to know about the main philosophical issues I am interested in. I want to explain how the brain of social animals, a biological organ, can make sense of the world. Using this approach I believe one can solve the main problems of the philosophy of science: the problem of the rationality of science and the problem of reality (does science give us the truth about the universe?). Darwin published The Origin of Species in 1859, but the biological revolution has not yet taken place for philosophy. Analytic philosophy, for example, has treated biology as an interloper in its (philosophy's) attempt to preserve what it takes to be the autonomy of philosophy (e.g., biological discussions of ethics commit the naturalistic fallacy, epistemology is prescriptive while biology is descriptive, etc.). So my job is to show that the so-called fallacies are not fallacious, that the only mistakes in reasoning are committed by the philosophers who discover them or who use them as the intellectual equivalent of slander. I see myself as clearing the philosophical rubble so that we may again have a worthwhile natural philosophy. I began this task in my Radical Knowledge in 1981, continued it in my Evolution and the Naked Truth in 1998, and will bring it all together in what I hope will be my best book on the subject, A Theory of Wonder.
I am also interested in showing very precisely why analytic philosophy is a dead end in every field: philosophy of science, epistemology, ethics, and especially philosophy of language, presumably its crowning glory. If I live long enough I should write it all up in a book titled Against Analysis.
PN: What projects are you currently working on?
GM: I am doing the final rewrite of The Dimming of Starlight: The Philosophy of Space Exploration. I am also doing a book in Spanish titled Variaciones sobre temas de Feyerabend ("Variations on themes by Feyerabend"). Right after these two I will finish rewriting A Theory of Wonder, which is my final commentary on the philosophy of science, and in which I give particular prominence to Feyerabend's work, all within the context provided by a biological approach to philosophy.
PN: In his How to defend Society against Science, Feyerabend was notorious for having given "three cheers to the creationists". What do you think of the current debate surrounding so-called Intelligent Design and/or Creationism and how do you see Feyerabend’s writings on "the tyranny of truth" and the separation of science and society applying to this controversy?
GM: Scientists and other reasonable people are quite right in pointing out that there is no worthwhile science in creationism or in intelligent design. So in that sense they are also quite right in keeping those subjects out of the science classroom. Giving equal time to all points of view in the classroom is one of the aspects of Feyerabend's Science in a Free Society that I criticized most strongly (see my paper in Beyond Reason). Nevertheless, I think that, if it were done right, it would be a terrific idea to pit intelligent design against evolutionary biology. It would be quite interesting for the students too: this is the accusation that creationists either of old or of "intelligent design" garb make against the theory of evolution; this is the reply. Done right it would be a rout in favor of evolution. And we would have American students actually understand biology for the first time in the history of the country. Unfortunately, most Americans, even scientists outside of biology, have little understanding of evolution. The fundamentalists should be careful about what they pray for, since if it is done properly it would give them fits. And they would have only themselves to blame. They often have no idea what the theory actually says. All they can think of is that we don't come from monkeys and God already wrote down for us in the Old Testament when the world began. The rest is a bunch of very confused notions about evolution and science.
I am afraid that it would not be done right, though. I have this vision of high school teachers parroting Popperian inanities. Still, they could clear up a lot of misconceptions about the fossil record, the evolution of complex organs, and so on.
My final take is that it would be an excellent way to teach evolution, but that I would feel more at ease if they put me in charge of training the biology teachers.
PN: What advice would you give to laymen interested in Feyerabend's thought but put off by the hostile reaction it got?
GM: If they are that easily led by the nose, I don't think they would be too interested in Feyerabend's work. As for those who are curious, I think that reading about him in less formal environments (this one, for example) can be helpful. Several good books on Feyerabend have been published and will continue to be published, but they tend to be written for specialists, and thus laymen may not take to them. Perhaps the most accessible is The Worst Enemy of Science? Essays in Memory of Paul Feyerabend, an anthology that I edited for Oxford with John Preston and David Lamb. I think that Feyerabend's reply to critics in Beyond Reason is very enjoyable, as are many of his shorter essays. His main works are quite challenging because of the extraordinary level of erudition and his uncompromising irony, even though he was a very good writer. People can read his autobiography, Killing Time, though. That is a very readable book. I am writing my A Theory of Wonder both for the layman and the specialist. I hope I will succeed.
In any event, people should bear in mind that Feyerabend is one of the most exciting philosophers in a long time. He was very irreverent, but he was also very insightful. If you want to experience a true challenge to the philosophical tradition, Feyerabend is your man.