Modern Science and Natural Philosophy

A short entry about modern science that originated from and also differs from ancient and medieval natural philosophy.

The term ‘science’ comes from the Latin word for knowledge, scientia. From our point of view, science is the systematic study of, or way of learning about, nature and the physical universe by means of the scientific method.

Essentially, the scientific method encompasses reproducible observations and experiments besides the asking of questions which, in turn, lead to the forming of hypotheses, the making of testable predictions and, then, the development of general theories. In the process, these hypotheses, predictions and theories are always subject to further observations as well as experimental testing.

As far as the study of nature as a separate subject was concerned, commonly employed expressions in the ancient, medieval and early modern periods were ‘philosophy of nature’ or ‘natural philosophy’. Correspondingly, the scholars engaged in it were called natural philosophers.

In general, natural philosophy in the ancient period and in the Middle Ages is different to the way of practicing science today. Unlike modern science, medieval natural philosophy – similar to the ancient philosophy of nature – lacked a tradition in experimentation. Accordingly, natural philosophers did not focus on direct observations and practical experiments.



Medieval Italy – The Birthplace of Glasses with an Unknown Creator (Part I)

Eyeglasses have been ranked among the most important inventions in human history. We don’t know exactly who invented spectacles. But, according to surviving historical sources, they first emerged in Italy during the Middle Ages. 

Glasses provide an enormous help for visually impaired people. They serve to correct defective eyesight – whether it is nearsightedness (i.e. myopia), farsightedness (i.e. hyperopia) or other vision disorders such as the aging eye condition (i.e. presbyopia).

Prototypically, these devices consist of a pair of glass or hard plastic lenses that are set in a frame. Through a bridge in addition to a nose pad as well as two arms the lenses are held in front of the eyes and the glasses rest on the nose and ears.

As far as the lenses are concerned, we usually distinguish between convex and concave lenses. The former bulge at the centre but are thinner around the edges, whereas the latter are, conversely, thinner in the middle and thicker at the edges. Furthermore, when light rays pass through these different types of lenses, in the convex lens the rays are converged at a focal point. By contrast, the concave lens diverges the beams.

Convex lenses help to treat farsightedness, while concave lenses are used in the treatment of nearsightedness. Alongside, for example, bifocal or multifocal lenses, which have two or more lens powers, convex lenses also (used to) correct presbyopia that occurs with aging eyes. In any case, Glasses enable people with visual impairment and the elderly whose eyesight deteriorates to (continue to) read and see properly.

Against this backdrop, it is unsurprising why academics have regarded eyeglasses as one of the most notable inventions in the history of mankind. For example, in a poll of more than 80 scholars, which was taken at the end of the 20th century, reading glasses were ranked among the most important inventions of the previous two millennia since they have significantly prolonged the active life of scholars and everybody who reads or is involved in fine and intellectual work.

Judging from surviving historical sources, glasses or spectacles first appeared in medieval Italy, even though the identity of the original inventor isn’t known. During the Middle Ages Catholic churchmen arguably encouraged the replication of eyeglasses and praised the art of spectacle making. This brings us to a sermon that was delivered in the first decade of the 14th century.

A Medieval Friar’s Praise of the art of making eyeglasses – Cues about Their Origin

On 23 February 1306 the Dominican friar Giordano da Pisa – one of the most popular preachers at this time – gave a sermon at the church Santa Maria Novella in Florence. At one point, he referred to the art of making spectacles:

It is not yet twenty years since there was found the art of making eyeglasses, which make for good vision, one of the best arts and most necessary that the world has. And it is so short a time that this new art, never before extant, was discovered. And the lecturer said: I saw the one who first discovered and practiced it, and I talked to him. (English translation taken from Vincent Illardi’s book Renaissance Vision from Spectacles to Telescopes (2007), p. 5).

His sermon contains some noteworthy cues about the origin of the art of spectacle construction, the importance of this art and the unknown inventor.

This photo was taken by me (Nils Zumbansen) in the church Santa Maria Novella in Florence (2018). My glasses are a bit anachronistic.

What strikes us immediately is the very beginning of the quotation as it indicates when the art of constructing eyeglasses was initially developed – approximately around 1285/6 or in the late 1280s. Roughly speaking, we can infer from archeological findings and historical as well as scholarly sources that spectacles, in fact, seem to have been invented or come into use in the period between the final decades of the 13th century and the early 14th century.

Interestingly enough, by the time Giordano delivered his sermon the production of spectacles was, for instance, well-established in two Italian city-states, Pisa and Venice. Especially the latter, the Republic of Venice, deserves a little closer look. Here the earliest reference to eyeglasses can be found in guild regulations which date from 1300. Consequently, medieval Italy justifiably qualifies as the birthplace of spectacles.

Apart from vaguely pointing to the time of their first appearance, the medieval friar Giordano da Pisa mentioned the positive effect of eyeglasses because of their ability to facilitate good vision. Moreover, he praised the art of spectacle making as one of the very best in the world. But in his sermon we don’t learn about the identity of the original inventor.

Who Was the Original Inventor of Eyeglasses? – An Unsolved and Probably Unsolvable Mystery

Before we turn to the issue of the unknown inventor, it is advisable to take into account  the fact that Giordano’s sermons were collected and recorded by loyal followers. Considering this, the Italian historian Chiara Frugoni asks the question whether the writer – by  adding the remark the lecturer said – meant Giordano, a teacher or theologian in Florence, or another scholar who was present during Giordano’s sermon and announced himself as a witness in this regard.

Whatever the case, instead of naming the inventor, Giordano or the other scholar just claimed to know him and to have talked to him. However, why didn’t the sermon reveal  his identity? We can only speculate.

All in all, the search for his name and identity has been an unsolved mystery and almost probably remains one. Some patriotically minded individuals, in particular during the 17th century, tried to identify the original inventor as an inhabitant of their local city. Despite their attempts, these theories prove to be unreliable and were already refuted.


Frugoni, Chiara. Medioevo sul naso. Occhiali, bottoni e altre invenzioni medievali. Rome, Bari: Editori Laterza, 2001.

Ilardi, Vincent. Renaissance Vision from Spectacles to Telescopes. Philadelphia: American Philosophical Society, 2007.

To be continued…The second part will present information about another important person in the history of spectacle making – Friar Alessandro della Spina. Additionally, it’ll be shown how medieval glasses looked like.