Why has the 18th and not the 19th century come to be called „the age of reason“?

Question

Not withstanding the romantic counter movement, nothing communicates to me the sense of belief in rationality and associated progress more than 19th century works. If I was to cite an emblematic book, it might be Jules Vernes‘ „Mysterious Isle“, where I get the sense that the resident engineers and botanists are able to solve just about any problem through their „modern“ scientific knowledge and empiricism.

If I were to compare this with Robinson Crusoe from the 18th century, he seems to me a great deal less capable and more reliant upon god.

It is true that great forebears of rationalism such as Hume and Locke and Kant all lived before the 19th century. But might it stand to reason that their works from the 17th and 18th century laid the groundwork for rationalism, which flourished in the 19th century? So much so that it produced a counter movement?

In the comments the example of economics was raised. Perhaps it’s a good analogy for what I suspect. Free trade ideas are very old and effectively defended by Adam Smith (died 1790). But my impression is that the 19th century is when these ideas came to gain wider acceptance and lead to abolition of the Corn Laws (1846) for instance. America can be said to have responded earlier (1776?).

if we take as the criterion not the first proponents, but the time when rationalism gained wide appeal and political consequence, isn’t the 19th century as good a candidate for the „Age of Reason“ as any?

I am aware that these are just sketchy thoughts. Perhaps not even substantial enough for a question. It so, could you please direct me to some literature which elucidates the relationship of the centuries as regards to rationalism?

Answer 1

FWIW, and IMHO, the age of reason is in full motion after the likes of Descartes, Newton, and Leibniz. The first systematized breaking down problems into bite sized chunks; the other two introduced calculus.

I'd further argue that the seeds were planted earlier, with the likes of Copernicus, Galileo, and Kepler. And that a key figure prior to that was Gutenberg. It's an understatement to suggest that very few inventions have had more impact on knowledge and on the way we exchange ideas in the past than the printing press. It's right up the list alongside the alphabet and the internet.

To me what characterizes the 18th century is the Enlightenment, which was as much about philosophy and political science as it was about science or systematizing rational thought. And what characterizes the 19th century are revolutions -- industrial of course, but also political, and fear of the latter.

Answer 2

It is true that great forebears of rationalism such as Hume and Locke and Kant all lived before the 19th century.

Your question is a bit vague. Yes, there were. It depends upon "what kind of genre" you are interested in.

For example, my university' major were mostly of Marx's and Engels' and other figures such as Dostoevsky, let me allow in my line the people who were the great thinkers before Locke, Kant, Hume etc.

Julien Offray de La Mettrie ( 1709-1751 ),Doctor, Thinker,

He thought the man is a machine. His/Her brain is the working muscle, that perceived the information from the sensory fingers ( or skins ). There is no spiritual a priori,

François Quesnay　（ 1694 - 1774 ), Doctor, economist.

His "Economic Table" shows how the products of farmers are provided in analytical way to the due receivers in ranks.

Well..if I have to take into account for Hume (1711-1766), these are the prominent figures I can count on and books of which I have read, if you say the "successor" of Hume.