We have come a long way from the classical ideal of objective descriptions.In quantum mechanics the departure from this ideal has been even more radical. We can still use the objectifying language of classical physics to make statements about observable facts. For instance, we can say that a photographic plate has been blackened, or that cloud droplets have formed. But we can say nothing about the atoms themselves.
Who sees the future? Let us have free scope for all directions of research; away with dogmatism, either atomistic or anti-atomistic!
It seems not absurd to conceive that at the first Production of mixt Bodies, the Universal Matter whereof they among other Parts of the Universe consisted, was actually divided into little Particles of several sizes and shapes variously mov'd.
Neither is it impossible that of these minute Particles divers of the smallest and neighbouring ones were here and there associated into minute Masses or Clusters, and did by their Coalitions constitute great store of such little primary Concretions or Masses as were not easily dissipable into such Particles as compos'd them.
I shall not peremptorily deny, that from most of such mixt Bodies as partake either of Animal or Vegetable Nature, there may by the Help of the Fire, be actually obtain'd a determinate number (whether Three, Four or Five, or fewer or more) of Substances, worthy of differing Denominations.
It may likewise be granted, that those distinct Substances, which Concretes generally either afford or are made up of, may without very much Inconvenience be call'd the Elements or Principles of them.
In 1738 Daniel Bernoulli correctly derived Boyle's law by assuming gases consisted of collections of particles that continuously collided with the container walls.
Dalton did not propose atoms as an abstraction or mathematical device; Dalton's atoms were physical. ...Despite its foundation in dubious hypothesis and its erroneous initial results, Dalton's theory was just the breakthrough that was needed. For the first time it allowed chemists to interpret mass relationships rationally.
Sweet exists by convention, bitter by convention, colour by convention; atoms and Void (alone) exist in reality.
By convention (νόμω) sweet is sweet, by convention bitter is bitter, by convention hot is hot, by convention cold is cold, by convention color is color. But in reality there are atoms and the void. That is, the objects of sense are supposed to be real and it is customary to regard them as such, but in truth they are not. Only the atoms and the void are real
If the idea of physical reality had ceased to be purely atomic, it still remained for the time being purely mechanistic; people still tried to explain all events as the motion of inert masses; indeed no other way of looking at things seemed conceivable. Then came the great change, which will be associated for all time with the names of Faraday, Clerk Maxwell, and Hertz.
The atomic theory was not generally accepted in the time of Democritus, largely because of its deterministic character, for it allows no chance, choice, or free will.
The thought of the great epistemological difficulties with which the visual atom concept of earlier physics had to contend gives us the hope that the abstracter atomic physics developing at present will one day fit more harmoniously into the great edifice of Science.
There is a fundamental error in separating the parts from the whole, the mistake of atomizing what should not be atomized. Unity and complementarity constitute reality.
Now his principal doctrines were these. That atoms and the vacuum were the beginning of the universe; and that everything else existed only in opinion.
However well fitted atomic theories may be to reproduce certain groups of facts, the physical inquirer who has laid to heart Newton's rules will only admit those theories as provisional helps. and will strive to attain, in some more natural way, a satisfactory substitute.
There is here a whole new branch of spectroscopy, which is sure to tell one much about the nature of an atom.
In... A New System of Chemical Philosophy published in 1808, John Dalton laid the foundations of the atomic theory: he assumed chemical action to be an action between very minute particles of elements and compounds, and all the minute particles of the same element, or compound, to be exactly the same size and weight. ...his hypothesis assumed the accuracy and universal applicability of those generalisations which are now called the laws of chemical combination.
If a fluid be composed of particles mutually flying [fleeing from] each other, and the density be as the compression, the centrifugal forces [repulsion] of the particles will be reciprocally proportional to the distances of their centres. And, vice versa, particles flying each other with forces that are reciprocally proportional to the distances of their centres, compose an elastic [liquid or gas], whose density is as the compression.
Dalton, the mathematical tutor, following up the lead of Newton, combined the whole of the results of quantitative measurement which had accumulated up to his time, in a comprehensive theory, based on the concept of the chemical atom.
The Atomic Theory and the Periodic Law have been given prominence, since their neglect unfailingly leads to obscurity and triviality.
The study of the radio-active substances and of the discharge of electricity through gases has supplied very strong experimental evidence in support of the fundamental ideas of the existing atomic theory. It has also indicated that the atom itself is not the smallest unit of matter but is a complicated structure made up of a number of smaller bodies.
The question whether our elementary atoms are in their nature indivisible, or whether they are built up of smaller particles, is one upon which I, as a chemist, have no hold whatever, and I may say that in chemistry the question is not raised by any evidence whatever.
The physical doctrine of the atom has got into a state which is strongly suggestive of the epicycles of astronomy before Copernicus.
And when Water and Oil of Vitriol poured successively into the same Vessel grow very hot in the mixing, does not this Heat argue a great Motion in the Parts of the Liquors? And does not this Motion argue, that the Parts of the two Liquors in mixing coalesce with Violence, and by consequence rush towards one another with an accelerated Motion?
And is it not from the mutual Attraction of the Ingredients that they stick together for compounding these Minerals... And the same Question may be put concerning all, or almost all the gross Bodies in Nature. For all the Parts of Animals and Vegetables are composed of Substances volatile and fix'd, fluid and solid, as appears by their Analysis; and so are Salts and Minerals, so far as Chymists have been hitherto able to examine their Composition.