Astronomical Observations relating to the Construction of the Heavens... (1811)
Context: I compared also the present appearance of this nebula with the delineation which Huyghens has given of it in his Systema Saturnium... The changes that are thus proved to have already happened, prepare us for those that may be expected hereafter to take place, by the gradual condensation of the nebulous matter; for had we no where an instance of any alteration in the appearance of nebula, they might be looked upon as permanent celestial bodies, and the successive changes, to which by the action of an attracting principle they have been conceived to be subject, might be rejected as being unsupported by observation.<!-- p. 324
“There are very few things that can be proved rigorously in condensed matter physics.”
Nobel Lecture http://www.nobelprize.org/nobel_prizes/physics/laureates/2003/leggett-lecture.pdf, December 8, 2003.
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Anthony James Leggett 3
British physicist 1938Related quotes
Source: An Invitation to Quantum Field Theory (2012), Ch. 1 : Why Do We Need Quantum Field Theory After All?
Neville Cardus, Foreword to All On A Summer's Day.
About
Part I, 4
The Kingfishers (1950)
Context: We can be precise. The factors are
in the animal and / or the machine the factors are
communication and / or control, both involve
the message. And what is the message? The message is
a discrete or continuous sequence of measurable events distributed in time is the birth of the air, is
the birth of water, is
a state between
the origin and
the end, between
birth and the beginning of
another fetid nest is change, presents
no more than itself And the too strong grasping of it,
when it is pressed together and condensed,
loses it This very thing you are
“The skin is impossibly wet, a cloud condensed into animate matter.”
"February 28th — Salamander," page 41
The Forest Unseen: A Year's Watch in Nature http://theforestunseen.com/ (2012)
“Very few experiments can, in the nature of things, be really crucial.”
Introduction
Higher Mathematics for Chemical Students (1911)
Context: It is necessary to guard against a possible danger... of submitting too readily to the result of a so-called "crucial experiment". Very few experiments can, in the nature of things, be really crucial. One so-called "crucial experiment" which decided between Newton's corpuscular theory of light and Huyghens' wave-theory, viz. the relation between the law of refraction and the velocity of light, was not at all decisive.
Astronomical Observations relating to the Construction of the Heavens... (1811)
Source: A Brief History of Time (1988), Ch. 1
Context: Any physical theory is always provisional, in the sense that it is only a hypothesis: you can never prove it. No matter how many times the results of experiments agree with some theory, you can never be sure that the next time the result will not contradict the theory. On the other hand, you can disprove a theory by finding even a single observation that disagrees with the predictions of the theory. As philosopher of science Karl Popper has emphasized, a good theory is characterized by the fact that it makes a number of predictions that could in principle be disproved or falsified by observation. Each time new experiments are observed to agree with the predictions the theory survives, and our confidence in it is increased; but if ever a new observation is found to disagree, we have to abandon or modify the theory.