In doing the research for something else, it occurred to me that not only do the meaning of words change but our understanding of what people might have thought, may have also changed. If words hold meaning and those words change, then do the underlying ideas get lost somehow?
Empedocles (c.450BC) conceived that the universe was made up of four "roots" (literally rhizomata) of earth, air, fire and water. I find it curious that these map nicely to the four states of matter which are solid, gas, plasma and liquid.
The Greeks also thought that if you were to keep on crushing things into ever smaller particles, eventually there would be the "atomon" or the "uncuttable". I also find it curious that with 21st century particle accelerators, we're still looking for (or maybe have found) elementary particles which include quarks, leptons and bosons.
Also as far as I can make out, the ancient world knew of thirteen things that we would consider "elements"; those being:
Gold, Silver, Copper, Zinc, Lead, Tin, Antimony, Iron, Mercury, Sulphur, Arsenic, Chromium and Carbon.
The Alchemists' dream of turning lead into gold is not only possible, it has been done; it's just that it is hideously expensive and doesn't make economic sense to pursue. To get at even the fourteenth element known, required German alchemist Hennig Brand, something in the order of 60 vats of urine, which he had to distill and then refine the residue. The ancient world already had a pretty good handle on the smelting of metals; so I doubt that their concept of "earth" was what we think that they think that it was.
I've batted liquid Mercury around a table top with a pen and I've even played the trick of making a spoon out of Gallium and smirking as it turns to liquid in the gentle warmth of someone's cup of tea. We've all seen ice, water and steam and so I'm wondering, if it's obvious to us that a liquid thing is made of the same stuff as a solid thing, why wouldn't the ancients have also noticed that? Just where would liquid and solid Mercury fit into the classical four roots?
Granted that science has taught us more "stuff" but are we actually any smarter? Ancient farmers knew that in order to prolong the life of a field, you had to rotate crops and then leave fields fallow for a time to rest. I think it strange that we can prove by experiment that global warming exists* and yet we still deliberately choose to buck the science.
I don't think that the ancient world was anywhere near as insensible or ignorant as we might suspect. People were more aware of the physical world around them and more than likely, knew how to interpret thing in their environment (like the weather) better than we do. I bet that they noticed far more different kinds of minerals than we do and smelled a far wider range of smells than we do, simply because they were outside and had far better practical training at it than we do.
The Greeks for instance referred to the sky as being bronze. Xenophanes described the rainbow as having three bands of color: purple, green/yellow, and red. I don't think that it was because he was colourblind but rather that there were different cultural connotations than we have. By comparison, there is no lead in a lead pencil and a Jerusalem Artichoke is not from Jerusalem and is not an artichoke.
The four roots of earth, air, fire and water, could very well have been a different sort of cultural designation for what kind of stuff stuff is, rather than the actual sort of stuff that stuff is made from. I don't know if it's fair to accuse them of being less smart.
*CO2 is 0.001977g/L whereas Air is 0.001280g/L
If we release more CO2 into a closed container (ie the atmosphere) then due to ideal gas laws, the temperature of those gases must rise. A denser gas in the same sized container should have more collisions between the molecules and therefore be warmer.