Austrian physicist and philosopher Ernst Mach's unique self-portrait, from the perspective of his left eye.
This unique self-portrait, also known as "view from the left eye", is the creation of Austrian physicist and philosopher Ernst Mach, noted for his contributions to physics such as the Mach number (which relates an object's speed to the speed of sound) and the study of shock waves. The sketch appears in Mach's The Analysis of Sensations, first published in German in 1886 as Beiträge zur Analyse der Empfindungen, and is used to illustrate his ideas about self-perception.
The considerations just advanced, expressed as they have been in an abstract form, will gain in strength and vividness if we consider the concrete facts from which they flow. Thus, I lie upon my sofa. If I close my right eye, the picture represented in the accompanying cut is presented to my left eye. In a frame formed by the ridge of my eyebrow, by my nose, and by my moustache, appears a part of my body, so far as visible, with its environment. My body differs from other human bodies beyond the fact that every intense motor idea is immediately expressed by a movement of it, and that, if it is touched, more striking changes are determined than if other bodies are touched by the circumstance, that it is only seen piecemeal, and, especially, is seen without a head. If I observe an element A within my field of vision, and investigate its connexion with another element B within the same field, I step out of the domain of physics into that of physiology or psychology, provided B, to use the apposite expression of a friend of mine made upon seeing this drawing, passes through my skin. Reflexions like that for the field of vision may be made with regard to the province of touch and the perceptual domains of the other senses.
In order to illustrate in a humorous manner this philosophical "much ado about nothing," and at the same time to shew how the self-inspection of the Ego could be really "carried out," I embarked on the above drawing. Mr L.'s society was most instructive and stimulating to me, owing to the naivety with which he gave utterance to philosophical notions that are apt to be carefully passed over in silence or involved in obscurity.
According to John Michael Krois the "Mr. L" in question is Mach's colleague at Prague University, Prof. Hermann von Leonhardi, son-in-law of the Kaul Christian Friedrich Krause mentioned. Krois also tells us that this original drawing sketched in 1870 in fact differed from the woodblock of 16 years later — the right arm with pencil is absent, with a left arm instead brandishing a cigarette (which has found its way to the mouth in the 1886 image), and a steaming cup of Viennese coffee sits on a small table.
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By libraryofbabel 2026-03-0716:531 reply The article mentions Mach numbers, but it leaves out what is most interesting about Mach’s place in the history of science, which is as a bridge to Einstein and General Relativity. Essentially Einstein read Mach and took a bunch of mind-bendingly profound but vague philosophical ideas like Mach’s Principle[0] and put together General Relativity out of it. And this self portrait gives that side of Mach too - the philosopher obsessed with phenomenology and how local perception relates to the large scale universe out there.
As a side note, Einstein read Mach but strongly opposed logical positivism[0].
[0]: https://philosophynow.org/issues/133/Einstein_vs_Logical_Pos...
By sigmoid10 2026-03-087:34 That is not what your source says. It gives one quote by him that may be misinterpreted in this context, but later clears up that Einstein was not really opposed. He merely thought that pure math was a valid way to discover new scientific insight. But even that point of view, while radical at the time, is pretty much in line with logical positivism and has turned out to be true many times since then.
I've always been struck by how long sentences are in writing from a century or more ago. To my mind whose attention-span has been poisoned by YouTube Shorts (even if they are mostly about trigonometry) and Tweets (even if I tell myself that's the new newspaper), they are most difficult to read. I often have to restart from the beginning.
Albeit an extreme example, here's a sentence from Henry James' "The Ambassadors", 1909:
The principle I have just mentioned as operating had been, with the most newly disembarked of the two men, wholly instinctive - the fruit of a sharp sense that, delightful as it would be to find himself looking, after so much separation, into his comrade's face, his business would be a trifle bungled should he simply arrange for this countenance to present itself to the nearing steamer as the first "note," of Europe.
By HPsquared 2026-03-0716:28 I remember reading the sentences in Adam Smith's "Wealth of Nations" and thinking this. A hell of a job to parse some of these.
Audiobook narrators often get it wrong reading these older texts, they'll put emphasis in the wrong place.
By gcanyon 2026-03-0723:21 Long sentences can serve as a way to break up the rhythm of prose: after a series of short sentences, a long sentence can force the reader to mentally "pause" to parse the contents of the sentence, or even just to figure out what the resulting sentence structure conveys, especially when a later part of the sentence calls back to an earlier part, turning the prose from a straightforward linear expression to a rhythmic loop, or even a self-referential construction.
Short sentences are fun too.
By jonahx 2026-03-0716:40 I recently picked up Washington Square, and while it has that old-fashioned flavor you describe, I was struck by how readable the long sentences and baroque turns of phrase were. They flow well, they're easy to parse. And the chapters have a Netflixy, binge-able quality. I got through it much faster than I expected.
By adonovan 2026-03-0722:21 Likewise! I often marvel at the patience of readers of earlier times. Of course, they had more time and fewer distractions, and I suspect that there was a dynamic at work in which both the writer and reader derived a certain satisfaction from long meandering sentences, the writer proving their skill, and the reader proving (to themselves) their stamina.
Nowadays we tend to write in a plainer style demanding a smaller “parser stack”. Some style manuals have excellent examples of sentences of equal length but very different “stack depth” and thus ease of comprehension.
By bookofjoe 2026-03-083:18 >I've always been struck by how long sentences are in writing from a century or more ago.
One book to rule them all:
https://dn721807.ca.archive.org/0/items/InSearchOfLostTimeCo...
Many one-sentence paragraphs extend for more than one page.
By B1FF_PSUVM 2026-03-083:57 > how long sentences are in writing from a century or more ago
Those were hunted down to extinction for ratings, about the time audience ratings were figured out. Not a reader left behind, so to speak ...
Most really deserved to be taken out and shot, they just demonstrated how lazy and unkempt the writer was. Editing was hell.
By dvh 2026-03-0716:48 > I've always been struck by how long sentences are in writing from a century or more ago
May I recommend Ulysses by James Joyce
By Jordan-117 2026-03-0716:352 reply I like how details fade around the edges -- though for maximum accuracy, there should only be a tiny area of high detail in the center, with most of the visual field being indistinct (as well as a total blind spot to one side). The brain just knows how to fill in remembered details of stuff you're not looking at directly, same way you tune out the sight of your own nose. Gaze-tracking and foveated rendering is a neat way of taking advantage of this quirk to speed up graphical processing:
And the eye's periphery, while it isn't sharp, is highly sensitive to movement. Which is "obvious" if you ponder the question where dangerous things appear first. Thus things dangling from the rear mirror in a car are a bad thing, they need (subconscious) attention.
The cone cells in the eye's center are color sensitive, but need a lot of light, while the rod cells at the edges are highly sensitive to motion, even in low light. And that might be one of the reasons why flicker is strenuous for the eyes. Funny side effect is that looking at stars in the night sky seems to work better when you look slightly besides a star, I guess that's because then the low light parts take over.
By martinpw 2026-03-0723:11 > Thus things dangling from the rear mirror in a car are a bad thing, they need (subconscious) attention.
And open offices with the associated foot traffic. Constant distraction quite apart from the noise factor.
By fwipsy 2026-03-0716:42 I would argue that the viewer's eye already provides this effect. Whichever part of the image you focus on is sharp; the rest is indistinct. The result is that we are drawn into the scene better; we see as if our eye were allowed to roam around the scene as his was, rather than seeing the much more limited perspective with a fixed gaze.
