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Perception and Discovery: An Introduction to Scientific Inquiry
Norwood Russell Hanson was one of the most important philosophers of science of the post-war period. Hanson brought Wittgensteinian ordinary language philosophy to bear on the concepts of science, and his treatments of observation, discovery, and the theory-ladenness of scientific facts remain central to the philosophy of science. Additionally, Hanson was one of philosophy’s great personalities, and his sense of humor and charm come through fully in the pages of Perception and Discovery . Perception and Discovery , originally published in 1969, is Hanson’s posthumous textbook in philosophy of science. The book focuses on the indispensable role philosophy plays in scientific thinking. Perception and Discovery features Hanson’s most complete and mature account of theory-laden observation, a discussion of conceptual and logical boundaries, and a detailed treatment of the epistemological features of scientific research and scientific reasoning. This book is of interest to scholars of philosophy of science, particularly those concerned with Hanson’s thought and the development of the discipline in the middle of the 20 th century. However, even fifty years after Hanson’s early death, Perception and Discovery still has a great deal to offer all readers interested in science.
435 pages, Paperback
First published January 1, 1958
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Displaying 1 - 6 of 6 reviews
December 25, 2017
A critique of empiricism, Hanson spells how and why we should realize that is our creative interpretations that are central to science. Drawing on Peirce he highlights the notion of retroduction, or what Peirce called abduction. I now feel that i get why this matters. His use of Kepler as a central example was especially helpful in getting his point across.
February 16, 2014
No es un libro sencillo de resumir pero para decir en pocas palabras mi opinión al leerlo diría que se evidencia por qué las ideas revolucionarias en él expresadas, junto con las de Wittgenstein en sus investigaciones filosóficas, fueron el sustento de la nueva filosofía de la ciencia: Hanson no fue un hombre de su tiempo y creo un libro un tanto engañoso: comienza de manera muy sencilla, con dibujitos en casi cada página del capítulo 1, el capítulo 2 tiene menos dibujos y menos ejemplos. A lo largo del los capítulos el libro se va complejizando hasta llegar a un punto (el de la física de las partículas elementales) que fue un tanto incomprensible para mi. No obstante lo anterior, y a pesar de mi poco instrucción en la física, pude encontrar la relación entre el capítulo 1 lleno de figuras y el capítulo 6 lleno de teorías cuánticas, eso demuestra que el libro está perfectamente estructurado y que no suelta al lector en ningún momento hasta que quedan completamente defendidos sus argumentos: "la abducción sobre la inducción y la deducción" y "toda observación está cargada de teoría".
February 13, 2026
I decided to read this book because Willard Humphreys makes good use of Norwood Hanson's concept of theory-laden seeing in his book Anomalies and scientific explanation. Reading through Hanson's original text displays well the more problematic aspects of that concept that were fine-tuned and improved upon by Humphreys. Hanson takes a much more explicitly pragmatist tack, with Wittgenstein and Peirce as his most important reference points. His approach is at its most interesting when dealing with Kepler's discovery of elliptical orbits, showing an insight to what could be called "conditions" of Newtonian style of science. There are trivially true segments on the unfalsifiability of physical laws which are then attached to a framework that reifies pattern-based intelligibility based on faulty analogies between observation and seeing.
Hanson's book could be construed as a footnote to Wittgenstein's duck-antelope point from Philosophical Investigations, so omnipresent is this basic idea throughout this book. He relies on examples such as Necker Cube and duck-antelope illusion as analogous to situations where physicists "see" the experimental equipment differently than a small child. He denies that this is due to interpretation by appealing to the Necker cube etc. Using this thought process, Hanson attempts to provide a theoretical support for the approach taken by modern particle physics where observation increasingly mixes with requirements of some theoretical intelligibility. Aside from Wittgenstein, he appeals to Peirce's notion of abductive inference and seems to consider it an adequate theoretical explanation even as it does not provide any support against alternate patterns or alternate cumulative progressions.
From the outset, Hanson's project fails due to the faulty analogy between the seeing processes inherent in Necker Cube type perspective switches and seeing as it takes place in experimental observation. His contention is that to deny their identity amounts to treating seeing as mere retinal images when in reality it must be considered theory-laden. He weaponizes an attractive truism in favour of a hasty identity of all phenomenal seeing, as if a child not seeing flask as a flask but rather as a shape would be the same as different interpretations of Necker Cube which are themselves based on more fundamental spatial features instead of theoretical concepts in the sense of "boiling flask". This is most easily shown by pointing out that these types of perceptual ambiguities are a feature of perception of the world as well (anything you see can be put on a screen so it is "really" two-dimensional) but unlike theory-laden viewing in Hanson's sense, they do not rely on accumulation of conceptual knowledge about extraneous functions objects ie. what types of thing "it" does.
Even the analogy between antelope-duck image and laboratory observation fails because the changing interpretations in the former do not involve a change in extrinsic theoretical functions of the image - for example, it is possible to be only aware of antelopes and still perceive the picture "wrong way around" without any predilection for perceiving antelopes. Another possibility is that the image may switch without any theory of whether it is one way or another, merely in terms of the unknown object. This is distinct from a case where I have theory of how a particular shape is connected to various behaviours and apply this notion: against Hanson, this is interpretation. Of course one may lump these phenomena together but this is to confuse the formal recognition of the object with connection of extraneous informations to it. Hanson, of course, defends this view against the background of increasingly functional perceptions of particles in the edifice of modern physics.
This approach normalizes the process of theory formation to the obvious and the analogy of Necker cubes begs the question with regards to the applicability of abductive inference and such since there is no correct answer as to what kind of an object Necker cube is - in fact, all spatial objects have at least a couple interpretations, indicating that the object itself is none of them. If anything, this goes against the criterion of mere intelligibility as sufficient. Even though there may be many interpretations of the flask object, it turns out to have certain limits but also certain possibilities which cannot be explored if the object has not been defined formally. It is a curious aspect of Hanson's theory that it is well designed to support cloud chamber physics but ill-fits any geometrical attempt at exploring the properties of geodesics, invariants etc. that are key features of the Einstein revolution. It also supports a normalized view of perception which, in fact, debilitates exploration: Hanson imagines that Copernicus seeing that Earth revolves around the Sun, as opposed Tycho Brahe, is the exact same thing as the shifting interpretations of a simple spatial object: when in reality, Copernicus sees the exact same thing as Tycho Brahe but interprets it with a different theory. Copernicus could perceive something like an ambiguity in the motion of a stellar object ie. whether it gets smaller or rotates which would affect the object on the object-level instead which would lead to whole new data-points instead of a new interconnection of existing ones.
All this is not to even speak of how this conception clashes with the way he keeps talking about science and observation. A problem even more basic than that just dealt with emerges: Hanson claims that layman must learn physics to see what the physicist sees. Fair enough but this means physics can never start since it is based on seeing. If seeing is always theory-laden in Hanson's sense and layman must learn physics before he can see physical objects, it seems impossible to ever actually discover a physical object. It is a conventionalist account that bypasses the painstaking sort of work people like Newton did in their experiments to ensure it hit exactly the property that needed to be studied. The same mistake appears in the concept of abductive inference , which starts from raw data, and how Hanson elsewhere explains that observation should start from data, ignoring the main thesis of his book, seeing is theory-laden, when he sees fit. There is a half-hearted attempt at appealing to a principle of "if your explanation is more simple, it is better"-type principle resemblant of Occam's Razor - but this is saying nothing until the precise relation of explanatory quality to virtuous simplicity is defined. Without definition of the former, I can "explain" things by saying "they just are" or "God did it" etc.
Overall, the book is an exercise in making misleading analogies to support a Wittgensteinian normalization of scientific procedure in technocratic New Deal America. It's interesting as a case study of an era which is now receding with the declining dominance of the USA but that's about it.
Hanson's book could be construed as a footnote to Wittgenstein's duck-antelope point from Philosophical Investigations, so omnipresent is this basic idea throughout this book. He relies on examples such as Necker Cube and duck-antelope illusion as analogous to situations where physicists "see" the experimental equipment differently than a small child. He denies that this is due to interpretation by appealing to the Necker cube etc. Using this thought process, Hanson attempts to provide a theoretical support for the approach taken by modern particle physics where observation increasingly mixes with requirements of some theoretical intelligibility. Aside from Wittgenstein, he appeals to Peirce's notion of abductive inference and seems to consider it an adequate theoretical explanation even as it does not provide any support against alternate patterns or alternate cumulative progressions.
From the outset, Hanson's project fails due to the faulty analogy between the seeing processes inherent in Necker Cube type perspective switches and seeing as it takes place in experimental observation. His contention is that to deny their identity amounts to treating seeing as mere retinal images when in reality it must be considered theory-laden. He weaponizes an attractive truism in favour of a hasty identity of all phenomenal seeing, as if a child not seeing flask as a flask but rather as a shape would be the same as different interpretations of Necker Cube which are themselves based on more fundamental spatial features instead of theoretical concepts in the sense of "boiling flask". This is most easily shown by pointing out that these types of perceptual ambiguities are a feature of perception of the world as well (anything you see can be put on a screen so it is "really" two-dimensional) but unlike theory-laden viewing in Hanson's sense, they do not rely on accumulation of conceptual knowledge about extraneous functions objects ie. what types of thing "it" does.
Even the analogy between antelope-duck image and laboratory observation fails because the changing interpretations in the former do not involve a change in extrinsic theoretical functions of the image - for example, it is possible to be only aware of antelopes and still perceive the picture "wrong way around" without any predilection for perceiving antelopes. Another possibility is that the image may switch without any theory of whether it is one way or another, merely in terms of the unknown object. This is distinct from a case where I have theory of how a particular shape is connected to various behaviours and apply this notion: against Hanson, this is interpretation. Of course one may lump these phenomena together but this is to confuse the formal recognition of the object with connection of extraneous informations to it. Hanson, of course, defends this view against the background of increasingly functional perceptions of particles in the edifice of modern physics.
This approach normalizes the process of theory formation to the obvious and the analogy of Necker cubes begs the question with regards to the applicability of abductive inference and such since there is no correct answer as to what kind of an object Necker cube is - in fact, all spatial objects have at least a couple interpretations, indicating that the object itself is none of them. If anything, this goes against the criterion of mere intelligibility as sufficient. Even though there may be many interpretations of the flask object, it turns out to have certain limits but also certain possibilities which cannot be explored if the object has not been defined formally. It is a curious aspect of Hanson's theory that it is well designed to support cloud chamber physics but ill-fits any geometrical attempt at exploring the properties of geodesics, invariants etc. that are key features of the Einstein revolution. It also supports a normalized view of perception which, in fact, debilitates exploration: Hanson imagines that Copernicus seeing that Earth revolves around the Sun, as opposed Tycho Brahe, is the exact same thing as the shifting interpretations of a simple spatial object: when in reality, Copernicus sees the exact same thing as Tycho Brahe but interprets it with a different theory. Copernicus could perceive something like an ambiguity in the motion of a stellar object ie. whether it gets smaller or rotates which would affect the object on the object-level instead which would lead to whole new data-points instead of a new interconnection of existing ones.
All this is not to even speak of how this conception clashes with the way he keeps talking about science and observation. A problem even more basic than that just dealt with emerges: Hanson claims that layman must learn physics to see what the physicist sees. Fair enough but this means physics can never start since it is based on seeing. If seeing is always theory-laden in Hanson's sense and layman must learn physics before he can see physical objects, it seems impossible to ever actually discover a physical object. It is a conventionalist account that bypasses the painstaking sort of work people like Newton did in their experiments to ensure it hit exactly the property that needed to be studied. The same mistake appears in the concept of abductive inference , which starts from raw data, and how Hanson elsewhere explains that observation should start from data, ignoring the main thesis of his book, seeing is theory-laden, when he sees fit. There is a half-hearted attempt at appealing to a principle of "if your explanation is more simple, it is better"-type principle resemblant of Occam's Razor - but this is saying nothing until the precise relation of explanatory quality to virtuous simplicity is defined. Without definition of the former, I can "explain" things by saying "they just are" or "God did it" etc.
Overall, the book is an exercise in making misleading analogies to support a Wittgensteinian normalization of scientific procedure in technocratic New Deal America. It's interesting as a case study of an era which is now receding with the declining dominance of the USA but that's about it.
May 26, 2024
My favorite nonfiction book.
May 23, 2024
Wow. Timeless and engaging, while still a challenging read. Like going back to Philosophy lectures from 50 yrs ago with exemplary exposition and argumentation. This type of writing, unfortunately rarely exists today. An interdisciplinary approach and I liked his inclusion of Wittgenstein's 'seeing'.
July 21, 2019
Very useful.
Displaying 1 - 6 of 6 reviews