“The casting of the net corresponds to observation; for knowledge which has not been or could not be obtained by observation is not admitted into physical science.
An onlooker may object that the first generalisation is wrong. "There are plenty of sea-creatures under two inches long, only your net is not adapted to catch them." The icthyologist dismisses this objection contemptuously.”

— Arthur Stanley Eddington

The Philosophy of Physical Science (1938)
Context: Let us suppose that an ichthyologist is exploring the life of the ocean. He casts a net into the water and brings up a fishy assortment. Surveying his catch, he proceeds in the usual manner of a scientist to systematise what it reveals. He arrives at two generalisations: No sea-creature is less than two inches long. (2) All sea-creatures have gills. These are both true of his catch, and he assumes tentatively that they will remain true however often he repeats it.
In applying this analogy, the catch stands for the body of knowledge which constitutes physical science, and the net for the sensory and intellectual equipment which we use in obtaining it. The casting of the net corresponds to observation; for knowledge which has not been or could not be obtained by observation is not admitted into physical science.
An onlooker may object that the first generalisation is wrong. "There are plenty of sea-creatures under two inches long, only your net is not adapted to catch them." The icthyologist dismisses this objection contemptuously. "Anything uncatchable by my net is ipso facto outside the scope of icthyological knowledge. In short, what my net can't catch isn't fish." Or — to translate the analogy — "If you are not simply guessing, you are claiming a knowledge of the physical universe discovered in some other way than by the methods of physical science, and admittedly unverifiable by such methods. You are a metaphysician. Bah!"

Adopted from Wikiquote. Last update June 3, 2021. History

Help us to complete the source, original and additional information

Do you have more details about the quote "The casting of the net corresponds to observation; for knowledge which has not been or could not be obtained by observa…" by Arthur Stanley Eddington?

Arthur Stanley Eddington photo

Arthur Stanley Eddington 105

British astrophysicist 1882–1944

Related quotes

“He arrives at two generalisations: No sea-creature is less than two inches long. (2) All sea-creatures have gills. These are both true of his catch, and he assumes tentatively that they will remain true however often he repeats it.”

Arthur Stanley Eddington (1882–1944) British astrophysicist

The Philosophy of Physical Science (1938)
Context: Let us suppose that an ichthyologist is exploring the life of the ocean. He casts a net into the water and brings up a fishy assortment. Surveying his catch, he proceeds in the usual manner of a scientist to systematise what it reveals. He arrives at two generalisations: No sea-creature is less than two inches long. (2) All sea-creatures have gills. These are both true of his catch, and he assumes tentatively that they will remain true however often he repeats it.
In applying this analogy, the catch stands for the body of knowledge which constitutes physical science, and the net for the sensory and intellectual equipment which we use in obtaining it. The casting of the net corresponds to observation; for knowledge which has not been or could not be obtained by observation is not admitted into physical science.
An onlooker may object that the first generalisation is wrong. "There are plenty of sea-creatures under two inches long, only your net is not adapted to catch them." The icthyologist dismisses this objection contemptuously. "Anything uncatchable by my net is ipso facto outside the scope of icthyological knowledge. In short, what my net can't catch isn't fish." Or — to translate the analogy — "If you are not simply guessing, you are claiming a knowledge of the physical universe discovered in some other way than by the methods of physical science, and admittedly unverifiable by such methods. You are a metaphysician. Bah!"

“[H]ow much of the fundamentals of Astronomy may be obtained with the coarsest observation with the unaided eye. …the science which is thus obtained by personal observations is vastly superior (as far as it goes) to that which is obtained by any other method. …The knowledge …inferred from actual personal observation carries with it a degree of reality and certainty, as the veritable science of external objects, which nothing else can give.”

George Biddell Airy (1801–1892) English mathematician and astronomer

Introduction
Popular Astronomy: A Series of Lectures Delivered at Ipswich (1868)

“A knowledge of the construction of the heavens has always been the ultimate object of my observations…”

William Herschel (1738–1822) German-born British astronomer, technical expert, and composer

Astronomical Observations relating to the Construction of the Heavens... (1811)

“Two normal observers viewing the same object from the same place under the same physical circumstances do not necessarily have identical visual experiences, even though the images on their respective retinas may be virtually identical.”

Alan Chalmers book What Is This Thing Called Science?

Source: What Is This Thing Called Science? (Third Edition; 1999), Chapter 1, Science as knowledge derived form the facts of experience, p. 5.

“The objects of abstract Geometry possess in absolute precision properties which are only approximately realized in the corresponding objects of physical Geometry.”

E. W. Hobson (1856–1933) British mathematician

Source: Squaring the Circle (1913), p. 5

“The Sea, once it casts its spell, holds one in its net of wonder forever.”

Jacques-Yves Cousteau (1910–1997) French naval officer, explorer, conservationist, filmmaker, innovator, scientist, photographer, author and …

“A physical theory, like an abstract science, consists of definitions and axioms as first principles, and of propositions, their consequences; but with these differences:—first, That in an abstract science, a definition assigns a name to a class of notions derived originally from observation, but not necessarily corresponding to any existing objects of real phenomena, and an axiom states a mutual relation amongst such notions, or the names denoting them; while in a physical science, a definition states properties common to a class of existing objects, or real phenomena, and a physical axiom states a general law as to the relations of phenomena; and, secondly,—That in an abstract science, the propositions first discovered are the most simple; whilst in a physical theory, the propositions first discovered are in general numerous and complex, being formal laws, the immediate results of observation and experiment, from which the definitions and axioms are subsequently arrived at by a process of reasoning differing from that whereby one proposition is deduced from another in an abstract science, partly in being more complex and difficult, and partly in being to a certain extent tentative, that is to say, involving the trial of conjectural principles, and their acceptance or rejection according as their consequences are found to agree or disagree with the formal laws deduced immediately from observation and experiment.”

William John Macquorn Rankine (1820–1872) civil engineer

Source: "Outlines of the Science of Energetics," (1855), p. 121; Second paragraph

“The men in the laboratory… cannot be said to observe the actual objects of their curiosity at all. …The sense data on which the propositions of modern science rest are, for the most part, little photographic spots and blurs, or inky curved lines on paper. …What is directly observable is only a sign of the "physical fact"; it requires interpretation to yield scientific propositions.”

Susanne K. Langer book Philosophy in a New Key

Philosophy in a New Key (1942)

“[A good teacher] brings knowledge and his pupil into a vital relationship; and the object of teaching is to establish that relationship on an intelligible basis. This can only be done … by appealing to two qualities which are at the bottom of all knowledge, curiosity and observation. They are born with us, every child naturally develops them, and it is the duty of the teacher to direct them to proper ends.”

Mandell Creighton (1843–1901) English historian and ecclesiastic

Thoughts on Education: Speeches and Sermons (1902)

“Attention or mindfulness is kept to a bare registering of the facts observed, without reacting to them by deed, speech or by mental comment which may be one of self-reference (like, dislike, etc.), judgment or reflection. If during the time, short or long, given to the practice of Bare Attention, any such comments arise in one’s mind, they themselves are made objects of Bare Attention, and are neither repudiated nor pursued, but are dismissed, after a brief mental note has been made of them.”

Nyanaponika Thera (1901–1994) German Buddhist monk

Source: The Heart of Buddhist Meditation (1965), p. 30

Related topics