Antiquity
Standard view in antiquity similar to Aristotelian physics is that the universe is finite and completely full. The question at that time was what is the universe filled of?
It was also thought for the universe to be infinitely divisible. This is based on Aristotle view of infinity =
- Infinite in extent / by addition
- infinitely divisible
Atomism emerged within against this background
- Atomic = indivisible
- this was first invented in the 5th century BCE by Leucippus and Democritus and furthered developed in Epicureanism
- believed that all material things are made of atoms, that atoms are the smallest thing (and indivisible), and that atoms exist in the void
- void = that which atoms are in and move through
- this opposed the traditional view in antiquity (established by Aristotle) in two main ways
- Atomist proposed that the universe is infinite
- proposed that the atoms are made of the same stuff, where Aristotle believed that each element was completely different and stuff
- Atoms differ from one another in only three ways:
- shape
- position
- arrangement
- According to Atomist, change is simply atoms in motion
- this view did not catch on until the 17th century when scientist were looking for an alternative to Aristotle
Views on the natural world
Experimental philosophy In Antiquity, it was believed that for science, we should be observing the world in its natural state. By Galileo’s time, scientists began to adopt a more experimental attitude towards science, in which they interfered and changed parameters in their experiment. This is characterized by Francis-bacon philosophy.
mechanical philosophy For the ancient Greeks, there was a dichotomy between nature vs art/technology/craft. But this broke down around the medieval time, and it was seen that in order to understand technology, you need to understand nature. The metaphor that was used at the time was “nature is like machine” such as the clock, The key component in these clocks was the escape wheel, which allowed the clock to run continuously and felt like this was a way towards matching nature with machinery. This view was later adopted by Descartes.
Robert Boyle (1627 - 1691)
Robert Boyle shared views with Descartes that all natural phenomena could be accounted for by the mechanical action of corpuscles (atoms or compounds of atoms).
Distinguishing his philosophy from Epicurean philosophy:
By embracing the corpuscular or mechanical philosophy, I am far from supposing with the Epicureans that atoms, accidentally meeting in an infinite vacuum were able, of themselves, to produce a world and all its phenomena: Nor do I suppose, when God had put into the whole mass of matter an invariable quantity of motion, he needed do no more to make the universe; the material parts being able, by their own unguided motions, to throw themselves into a regular system. The philosophy I plead for reaches but to things purely corporeal; and distinguishing between the first origin of things and the subsequent course of nature, teaches that God indeed gave motion to matter; but that, in the beginning, he so guided the various motions of the parts of it as to contrive them into the world he designed that they should compose; and established those rules of motion, and that order amongst things corporeal, which we call the laws of nature.
Boyle disagrees with Epicurean philosophy that atoms do not accidently move to form the world and the phenomena that we see. Boyle sees that God endowed atoms with the internal purpose of motion and rules of motion, i.e. the laws of nature
Boyle argues that the laws of nature are universal and that there isn’t a distinction between the sub-lunar realm and the heavens that Aristotle postulated.
Properties of Corpuscles according to Boyle
The next thing which recommends the corpuscular principles is their extensiveness. The genuine and necessary effect of the strong motion of one inert particle of matter against another is either to drive it on, in its entire bulk, or to break and divide it into particles of a determinate motion, figure, size, posture, rest, order or texture.
This is taken matter as inert or passive.
- Bulk = mass
- Figure = shape
- Size
- Posture = position relative to another corpuscle (vertical, horizontal, or inclined)
- Order = arrangement
- Texture = the result of when corpuscles are woven together
- Motion or rest
For the solidity, taste, etc., of salt may be fairly accounted for by the stiffness, sharpness, and other mechanical properties of the minute particles whereof salt consists
During the late 1650s and early 1660s, Boyle created out a number of experiments using the first air pump and vacuum. His findings were published in New experiments Physico-Mechanical, Touching the Spring of Air regarding the properties of air, proving that sound cannot travel in a vacuum, that air is required for animal respiration, that fire needs air, etc.
18th century Pneumatic Chemistry
Pneumatic chemistry = chemistry of gases
Before the 18th century, air was seen as a single substance, one of the four Aristotelian elements. Investigating the chemical properties of air was an 18th century innovation, as in the 17th century chemists usually assumed that air was chemically inert and played no role in chemical reactions.
Georg Ernst Stahl (1660-1734)
- Prussian physician and chemist
- thought chemists should be analyzing chemical compounds
Stephen Hales (1677-1761)
- Reverend, botanist + chemist
- created the pneumatic (air) trough = have the air from a chemical reaction pass through a vessel, a long curved neck and water in a trough to purify, then captured in an inverted vessel
Joseph Black (1728-99)
- Chemist, fixed air (discovered),
- discovered fixed air (Carbon dioxide)
- experimented on magnesia alba (magnesium carbonate) which when heated up yields a gas that when passed through lime water turned it milky
- named it fixed air because it is fixed in place within a solid
Joseph Priestley (1733 - 1804)
- building on Hale’s and Black’s observations, Priestley established the existence of a number of different kinds of air, each with specific properties
- discovered nitrous air (nitrous dioxide or laughing gas)
- discovered dephlogisticated air (oxygen)
By heating red calx of mercury, Priestley produced an air that seemed to contain little to no phlogiston.
- Priestley saw it as the best kind of air possible
- argued that the best kind of airs for human life were those that contained the least phlogiston
- called it “vital air”
- hospitable for both life and combustion
There wasn’t a combination of atomic theory and chemical theory until John Dalton (1766 - 1844), where he hypothesizes that each element has its own atom associated to it. He works with this assumption to figure out the weight of the atom, which leads to the combination of atomic and chemical theory.
Mixts - Chemical compounds
Mixtion - Mixtures (chemical reactions/change)
Oxide (calx) - Oxygen combined with a metal
Metals were thought as compounds, not its own element
Plants absorbed phlogiston from the atmosphere (that’s why trees could burn)
Mercurius calcinatus (mercurous oxide, HgO) - Red precipitate, when heated, produced a “new” air that caused fire to burn more vigorously