Philipp Berghofer

Although contemporary analytic epistemology continues to be dominated by externalist accounts, an alternative internalist approach has recently emerged that emphasizes the epistemic role of consciousness, in particular of conscious experience. According to the phenomenological experience-first epistemology (PEFE) discussed in this paper, certain experiences constitute a source of immediate justification as well as our ultimate evidence. One reason why internalist approaches are less popular in current debates is the common assumption that externalism fits better with scientific practice. In this picture, the natural sciences are typically understood as adopting a third-person perspective that successfully abstracts away from the subject and her personal experiences. Here, I discuss an alternative view of science, namely science as understood within the framework of agent-centered approaches to quantum mechanics. More specifically, my focus will be on QBism, a highly controversial but increasingly popular interpretation of quantum mechanics, whose defining feature is the interpretation of quantum probabilities as subjective Bayesian probabilities. The objective of this paper is to clarify the relationship between epistemology and science under the assumption that both PEFE and QBism are correct.

Husserl claims that his phenomenological–epistemological system amounts to a “universal” form of empiricism. The present paper shows that this universal moment of Husserl’s empiricism is why his empiricism qualifies as a rationalism. What is empiricist about Husserl’s phenomenological–epistemological system is that he takes experiences to be an autonomous source of immediate justification. On top of that, Husserl takes experiences to be the ultimate source of justification. For Husserl, every justified belief ultimately depends epistemically on the subject’s experiences. These are paradigms of empiricist claims and thus Husserl seems to subscribe to empiricism. However, what is universal about Husserl’s “empiricism” is that he does not limit the concept of (justification-conferring) experiences to sensory experiences or sensory experiences plus introspective intuitions but broadens the concept of experience such that also a priori intuitions are included. Husserl insists that logical, mathematical, and phenomenological intuitions such as ~ (p ∧ ~ p), 2 + 2 = 4, and “Experiences necessarily bear the mark of intentionality” provide non-inferential justification analogous to how sensory experiences can non-inferentially justify beliefs such as “There is a table in front of me.” Importantly, Husserl makes clear that such a priori intuitions are not about our concepts but about reality. This is why Husserl’s universal empiricism is a rationalism. Husserl differs from traditional rationalism as he allows that a priori intuitions can be fallible and empirically underminable. This distinguishes Husserl’s rationalism from Descartes’ and makes him a proponent of moderate rationalism as currently championed by Laurence BonJour.

ABSTRACT Perceptual experiences justify. When I look at the black laptop in front of me and my perceptual experience presents me with a black laptop placed on my desk, my perceptual experience has justificatory force with respect to the proposition that there is black laptop on the desk. The present paper addresses the question of why perceptual experiences are a source of immediate justification: What gives them their justificatory force? I shall argue that the most plausible and the most straightforward answer to this question consists in what I call the phenomenological conception of perceptual justification. Perceptual experiences justify by virtue of their distinctive presentive phenomenology. This is a truly internalist conception that enjoys significant advantages over rival conceptions. In the course of his paper, I demonstrate the advantages of the phenomenological conception and defend it against a recent objection.

Recently, perceptual learning has become a focus of philosophical investigations. This is because the phenomenon of perceptual learning sheds light on the nature of perception. It tells us that the physical objects that are perceived are not the sole causes of perceptual states, it reveals that previous experiences shape the way we perceive, and it brings into focus an experience’s phenomenal character. Hence, there is no doubt that perceptual learning has crucial implications for philosophy of mind. Only very recently, however, have researchers begun to investigate whether we can draw genuinely epistemological lessons from perceptual learning. In the first section, we shall see that such epistemological lessons do indeed exist. The rest of the paper is devoted to showing that there are analogous cases of intuitional learning. By discussing simple examples, it is argued that such cases of intuitional learning suggest that intuitions are sui generis mental states, namely experiences that have a distinctive phenomenal character, and that it is this distinctive phenomenal character that makes intuitions a source of immediate justification.

Although contemporary analytic epistemology continues to be dominated by externalist accounts, an alternative internalist approach has recently emerged that emphasizes the epistemic role of consciousness, in particular of conscious experience. According to the phenomenological experience-first epistemology (PEFE) discussed in this paper, certain experiences constitute a source of immediate justification as well as our ultimate evidence. One reason why internalist approaches are less popular in current debates is the common assumption that externalism fits better with scientific practice. In this picture, the natural sciences are typically understood as adopting a third-person perspective that successfully abstracts away from the subject and her personal experiences. Here, I discuss an alternative view of science, namely science as understood within the framework of agent-centered approaches to quantum mechanics. More specifically, my focus will be on QBism, a highly controversial but increasingly popular interpretation of quantum mechanics, whose defining feature is the interpretation of quantum probabilities as subjective Bayesian probabilities. The objective of this paper is to clarify the relationship between epistemology and science under the assumption that both PEFE and QBism are correct.

There is solid consensus among physicists and philosophers that, in gauge field theory, for a quantity to be physically meaningful or real, it must be gauge-invariant. Yet, every “elementary” field in the Standard Model of particle physics is actually gauge-variant. This has led a number of researchers to insist that new manifestly gauge-invariant approaches must be established. Indeed, in the foundational literature, dissatisfaction with standard methods for reducing gauge symmetries has been expressed: Spontaneous symmetry breaking is deemed conceptually dubious, while gauge fixing suffers the same limitations and is subject to the same criticisms as coordinate choices in General Relativity. An alternative gauge-invariant proposal was recently introduced in the literature, the so-called “dressing field method” (DFM). It is a mathematically subtle tool, and unfortunately prone to be confused with simple gauge transformations, hence with standard gauge fixings. As a matter of fact, in the physics literature the two are often conflated, and in the philosophy community some doubts have been raised about whether there is any substantial difference between them. Clarifying this issue is of special significance for anyone interested in both the foundational issues of gauge theories and their invariant formulation. It is thus our objective to establish as precisely as possible the technical and conceptual distinctions between the DFM and gauge fixing.

Gauge symmetries play a central role, both in the mathematical foundations as well as the conceptual construction of modern (particle) physics theories. However, it is yet unclear whether they form a necessary component of theories, or whether they can be eliminated. It is also unclear whether they are merely an auxiliary tool to simplify (and possibly localize) calculations or whether they contain independent information. Therefore their status, both in physics and philosophy of physics, remains to be fully clarified. In this overview we review the current state of affairs on both the philosophy and the physics side. In particular, we focus on the circumstances in which the restriction of gauge theories to gauge invariant information on an observable level is warranted, using the Brout-Englert-Higgs theory as an example of particular current importance. Finally, we determine a set of yet to be answered questions to clarify the status of gauge symmetries.

The program of reconstructing quantum theory based on information-theoretic principles enjoys much popularity in the foundations of physics. Surprisingly, this endeavor has only received very little attention in philosophy. Here I argue that this should change. This is because, on the one hand, reconstructions can help us to better understand quantum mechanics, and, on the other hand, reconstructions are themselves in need of interpretation. My overall objective, thus, is to motivate the reconstruction program and to show why philosophers should care. My specific aims are threefold. (i) Clarify the relationship between reconstructing and interpreting quantum mechanics, (ii) show how the informational reconstruction of quantum theory puts pressure on standard realist interpretations, (iii) defend the quantum reconstruction program against possible objections.

In quantum foundations, there is growing interest in the program of reconstructing the quantum formalism from clear physical principles. These reconstructions are formulated in an operational framework, deriving the formalism from information-theoretic principles. It has been recognized that this project is in tension with standard _ψ-ontic_ interpretations. This paper presupposes that the quantum reconstruction program (QRP) (i) is a worthwhile project and (ii) puts pressure on _ψ-ontic_ interpretations. Where does this leave us? Prima facie, it seems that _ψ-epistemic_ interpretations perfectly fit the spirit of information-based reconstructions. However, _ψ-epistemic_ interpretations, understood as saying that the wave functions represents one’s _knowledge_ about a physical system, recently have been challenged on technical and conceptual grounds. More importantly, for some researchers working on reconstructions, the lesson of successful reconstructions is that the wave function does _not_ represent objective facts about the world. Since knowledge is a factive concept, this speaks against epistemic interpretations. In this paper, I discuss whether _ψ-doxastic_ interpretations constitute a reasonable alternative. My thesis is that if we want to engage QRP with _ψ-doxastic_ interpretations, then we should aim at a reconstruction that is spelled out in non-factive experiential terms.

In his influential paper “Grasping the Third Realm,” John Bengson raises the question of how we can non-accidentally grasp abstract facts. What distinguishes successful intuition from hallucinatory intuition? Bengson answers his “non-accidental relation question” by arguing for a constitutive relationship: The intuited object is a literal constituent of the respective intuition. Now, the problem my contribution centers around is that Bengson’s answer cannot be the end of the story. This is because, as Bar Luzon and Preston Werner have recently pointed out, this answer leads to the follow-up question of why certain intuitional experiences are constituted by the facts, but others are not. My objective is to answer this question by specifying precisely what is epistemically defective about intellectual hallucinations. My result is that, in stark contrast to perception, intellectual hallucinations are epistemically defective in the sense that something is overlooked. In successful intuition, by contrast, all relevant possibilities/scenarios are considered/imagined. This has crucial epistemological implications. In particular, I argue that intuitions exhibiting a certain phenomenology cannot fail to successfully grasp abstract facts. I call this the non-accidental correctness thesis, which constitutes the main thesis of this paper.

Phenomenologically, perception distinguishes itself from other modes of consciousness by presenting its objects and contents “in the flesh;” it has a presentive character. From the first person perspective, there is a clear difference between thinking about a laptop on the desk, imagining a laptop on the desk, believing or hoping that there is a laptop on the desk, and actually visually perceiving a laptop on the desk. Only perception has a presentive character with respect to physical objects. Epistemologically, perception distinguishes itself by being a source of immediate justification for beliefs about physical states of affairs. Believing, imagining, or hoping that there is a laptop on the desk does not justify a person in believing so. However, if the person sees that there is a laptop on the desk, it is plausible to assume that she is thereby justified in believing that there is a laptop on the desk. Only perception is a source of immediate justification with respect to such states of affairs. In the phenomenological as well as in the recent analytic tradition, there have been attempts to connect the phenomenological and the epistemological distinctiveness of perception: It has been argued that perception is a source of immediate justification precisely by virtue of its presentive phenomenal character. In the analytic tradition, however, it has been often overlooked that the phenomenal character of perception is not exhausted by its presentive character. Perception, essentially, also has a co-presenting character; it has a horizontal structure. The aim of this paper is to shed light on the epistemological significance of the horizontal structure of perception.

In 1967, Alvin Goldman prominently claimed that the traditional JTB analysis is adequate for non-empirical knowledge. Since then, this claim has remained widely unchallenged. In this paper, I show that this claim is false. I provide two examples in which a true belief is a priori justified but epistemically defective such that it does not constitute knowledge. Finally, I submit a novel analysis of a priori knowledge that avoids the Gettier problem. What is particularly important and distinctive about my analysis is that I neither need to make the justification condition so strong that only infallible justification is allowed, nor do I need to explicitly introduce a truth condition.

This chapter introduces time travel into the Star Wars lore. Time travel stories in which the past is changed are in danger of being inconsistent or plagued by paradoxes. In famous time travel stories such as Back to the Future, the protagonist travels to the past, changes the past, and then returns to a present quite different from the one they left. In contemporary philosophy of time, there are three main approaches to this question: presentism, eternalism, and the growing block universe. Time travel works by entering a place, the World Between Worlds, that connects different points in time and space. In terms of modern physics, the portals in the World Between Worlds may be understood as traversable wormholes. The nature of time and the possibility of time travel have attracted and captivated humanity for centuries.

In the Marvel Cinematic Universe (MCU), according to the Ancient One, magic is created by drawing energy from the other dimensions of the multiverse. This sounds like a concept from science fiction, but the idea that people are living in a vast multiverse is very possibly science fact. A recurring and especially important theme in Doctor Strange is the role that human beings are supposed to play in the universe. The concept of the multiverse is well established in the Marvel comics and has officially been introduced into the MCU, and the way it is introduced touches on central issues in the philosophy of physics. Quantum mechanics is hands‐down one of the greatest accomplishments of science. Understanding the apparent collapse of the wave function upon observation is the core of the measurement problem. There are different ways of explaining this, which are called “interpretations” of quantum mechanics.

Husserl argued that psychology needs to establish an abstraction that is opposite to the abstraction successfully established in the natural sciences. While the natural sciences abstract away the psychological or subjective, psychology must abstract away the physical or worldly. However, Husserl and other phenomenologists such as Iso Kern have argued that there is a crucial systematic disanalogy between both abstractions. While the abstraction of the natural sciences can be performed completely, the abstraction of psychology cannot. In this context, Husserl argues that the psychological reduction leads to paradoxes. In this paper, I critically discuss whether it is true that the natural sciences can successfully abstract away the subjective. Or more precisely, I raise the question of whether they should.

This volume brings together philosophers and physicists to explore the parallels between Quantum Bayesianism, or QBism, and the phenomenological tradition. It is the first book exclusively devoted to phenomenology and quantum mechanics. By emphasizing the role of the subject's experiences and expectations, and by explicitly rejecting the idea that the notion of physical reality could ever be reduced to a purely third-personal perspective, QBism exhibits several interesting parallels with phenomenology. The central message of QBism is that quantum probabilities must be interpreted as the experiencing agent's personal Bayesian degrees of belief--degrees of belief for the consequences of their actions on a quantum system. The chapters in this volume elaborate whether and specify how phenomenology could serve as the philosophical foundation of QBism. This objective is pursued from the perspective of QBists engaging with phenomenology as well as the perspective of phenomenologists engaging with QBism. These approaches enable us to realize a better understanding of quantum mechanics and the world we live in, achieve a better understanding of QBsim, and introduce the phenomenological foundations of quantum mechanics. Phenomenology and QBism is an essential resource for researchers and graduate students working in philosophy of physics, philosophy of science, quantum mechanics, and phenomenology.

This book offers a phenomenological conception of experiential justification that seeks to clarify why certain experiences are a source of immediate justification and what role experiences play in gaining (scientific) knowledge. Based on the author's account of experiential justification, this book exemplifies how a phenomenological experience-first epistemology can epistemically ground the individual sciences. More precisely, it delivers a comprehensive picture of how we get from epistemology to the foundations of mathematics and physics. The book is unique as it utilizes methods and insights from the phenomenological tradition in order to make progress in current analytic epistemology. It serves as a starting point for re-evaluating the relevance of Husserlian phenomenology to current analytic epistemology and making an important step towards paving the way for future mutually beneficial discussions. This is achieved by exemplifying how current debates can benefit from ideas, insights, and methods we find in the phenomenological tradition.

Evidentialism and mentalism enjoy much popularity. In fact, mentalist evidentialism is often considered the most plausible internalist approach towards epistemic justification. However, mentalist evidentialism does not amount to a comprehensive theory of epistemic justification. In their attempt to complete their epistemological system and to answer the question of why experiences are justifiers, Conee and Feldman supplement mentalist evidentialism with explanationism. They take principles of best explanation to be the fundamental epistemic principles. In this paper, I show that explanationist mentalist evidentialism is plagued by severe shortcomings. What is more, I argue for an alternative in the spirit of Conee and Feldman's internalism that avoids the problems of explanationism, offering a straightforward commonsense account of epistemic justification. The fundamental epistemological principles are phenomenological principles.

This book offers fresh perspective on the role of phenomenology in the philosophy of physics which opens new avenues for discussion among physicists, "standard" philosophers of physics and philosophers with phenomenological leanings. Much has been written on the interrelations between philosophy and physics in the late 19th and early 20th century, and on the emergence of philosophy of science as an autonomous philosophical sub-discipline. This book is about the under-explored role of phenomenology in the development and the philosophical interpretation of 20th century physics. Part 1 examines questions about the origins and value of phenomenological approaches to physics. Does the work of classical phenomenologists such as Husserl, Merleau-Ponty or Heidegger contain elements of systematic value to both the practice and our philosophical understanding of physics? How did classical phenomenology influence “standard” philosophy of science in the Anglo-American and other traditions? Part 2 probes questions on the role of phenomenology in the philosophies of physics and science: - Can phenomenology help to solve “Wigner’s puzzle”, the problem of the "unreasonable effectiveness" of mathematics in describing, explaining and predicting empirical phenomena? - Does phenomenology allow better understanding of the principle of gauge invariance at the core of the standard model of contemporary particle physics? - Does the phenomenological notion of “Lifeworld” stand in opposition to the “scientific metaphysics” movement, or is there potential for dialogue? Part 3 examines the measurement problem. Is the solution outlined by Fritz London and Edmond Bauer merely a re-statement of von Neumann’s view, or should it be regarded as a distinctively phenomenological take on the measurement problem? Is phenomenology a serious contender in continuing discussions of foundational questions of quantum mechanics? Can other interpretational frameworks such as quantum Bayesianism benefit from implementing phenomenological notions such as constitution or horizonal intentionality?

Recently, a number of phenomenological approaches to experiential justification emerged according to which an experience's justificatory force is grounded in the experience’s distinctive phenomenology. The basic idea is that certain experiences exhibit a presentive phenomenology and that they are a source of immediate justification precisely by virtue of their presentive phenomenology. Such phenomenological approaches usually focus on perceptual experiences and mathematical intuitions. In this paper, I aim at a phenomenological approach to ethical experiences. I shall show that we need to make a distinction between evaluative experiences directed at concrete cases and ethical intuitions directed at general principles. The focus will be on evaluative experiences. I argue that evaluative experiences constitute a sui generis type of experience that gain their justificatory force by virtue of their presentive evaluative phenomenology. In Sect. 1, I introduce and motivate the phenomenological idea that certain experiences exhibit a justification-conferring phenomenology. In Sect. 4, I apply this idea to morally evaluative experiences. In Sect. 5, I suggest that certain epistemic intuitions should be considered epistemically evaluative experiences and I outline a strong parallelism between ethics and epistemology.

As is well known, the late Husserl warned against the dangers of reifying and objectifying the mathematical models that operate at the heart of our physical theories. Although Husserl’s worries were mainly directed at Galilean physics, the first aim of our paper is to show that many of his critical arguments are no less relevant today. By addressing the formalism and current interpretations of quantum theory, we illustrate how topics surrounding the mathematization of nature come to the fore naturally. Our second aim is to consider the program of reconstructing quantum theory, a program that currently enjoys popularity in the field of quantum foundations. We will conclude by arguing that, seen from this vantage point, certain insights delivered by phenomenology and quantum theory regarding perspectivity are remarkably concordant. Our overall hope with this paper is to show that there is much room for mutual learning between phenomenology and modern physics.

Experimental philosophy is often considered a novel and exciting movement in philosophy that paves the way for new ways of interdisciplinary research and offers an unprecedented methodology that allows gaining unexpected results that could revolutionize philosophical research. In this paper, however, we shall see that the methodology of experimental philosophy has been well-known and even practiced at Meinong’s Graz school of object theory and experimental psychology. This is particularly true for the works of Vittorio Benussi that can be regarded as an experimental confirmation of some of Husserl’s central theses. We shall also shed light on some shortcomings of how experimental philosophy is currently practiced and argue for bringing an intuition-free experimental philosophy into focus. In the final section, we will see that Benussi’s experimental research qualifies as such an intuition-free experimental philosophy.

In current debates, many philosophers of science have sympathies for the project of introducing a new approach to the scientific realism debate that forges a middle way between traditional forms of scientific realism and anti-realism. One promising approach is perspectivism. Although different proponents of perspectivism differ in their respective characterizations of perspectivism, the common idea is that scientific knowledge is necessarily partial and incomplete. Perspectivism is a new position in current debates but it does have its forerunners. Figures that are typically mentioned in this context include Dewey, Feyerabend, Leibniz, Kant, Kuhn, and Putnam. Interestingly, to my knowledge, there exists no work that discusses similarities to the phenomenological tradition. This is surprising because here one can find systematically similar ideas and even a very similar terminology. It is startling because early modern physics was noticeably influenced by phenomenological ideas. And it is unfortunate because the analysis of perspectival approaches in the phenomenological tradition can help us to achieve a more nuanced understanding of different forms of perspectivism. The main objective of this paper is to show that in the phenomenological tradition one finds a well-elaborated philosophy of science that shares important similarities with current versions of perspectivism. Engaging with the phenomenological tradition is also of systematic value since it helps us to gain a better understanding of the distinctive claims of perspectivism and to distinguish various grades of perspectivism.

The aim of this paper is to establish a phenomenological mathematical intuitionism that is based on fundamental phenomenological-epistemological principles. According to this intuitionism, mathematical intuitions are sui generis mental states, namely experiences that exhibit a distinctive phenomenal character. The focus is on two questions: what does it mean to undergo a mathematical intuition and what role do mathematical intuitions play in mathematical reasoning? While I crucially draw on Husserlian principles and adopt ideas we find in phenomenologically minded mathematicians such as Hermann Weyl and Kurt Gödel, the overall objective is systematic in nature: to offer a plausible approach towards mathematics.

Husserl’s transcendental phenomenology is first and foremost a science of the structures of consciousness. Since it is intended to yield eidetic, i. e., a priori insights, it is often assumed that transcendental phenomenology and the natural sciences are totally detached from each other such that phenomenological investigations cannot possibly benefit from empirical evidence. The aim of this paper is to show that a beneficial relationship is possible. To be more precise, I will show how Husserl’s a priori investigations on consciousness can be supplemented by research in experimental psychology in order to tackle fundamental questions in epistemology. Our result will be a phenomenological conception of experiential justification that is in accordance with and supported by empirical phenomena such as perceptual learning and the phenomenon of blindsight. Finally, I shall shed light on the systematic limits of empirical research.

Perceptual experiences justify. When I look at the black laptop in front of me and my perceptual experience presents me with a black laptop placed on my desk, my perceptual experience has justificatory force with respect to the proposition that there is black laptop on the desk. The present paper addresses the question of why perceptual experiences are a source of immediate justification: What gives them their justificatory force? I shall argue that the most plausible and the most straightforward answer to this question consists in what I call the phenomenological conception of perceptual justification. Perceptual experiences justify by virtue of their distinctive presentive phenomenology. This is a truly internalist conception that enjoys significant advantages over rival conceptions. In the course of his paper, I demonstrate the advantages of the phenomenological conception and defend it against a recent objection.