• In piano, left side's note sounds lower in frequency than the right side.
  • When we write a timeline diagram, the left side's year comes before right side's.
  • When we order books on the shelf, usually the volumes are ordered increasingly from left to right.
  • Many reading system also goes from left to right. Few languages goes from right to left or up to down. I also might want to ask why up seems to be usually "more" than down.

For up and down, I guess it might be related to gravity that we developed that mindset of up is higher/better/more than down. But I could not think of any natural things that goes from left to right other than many man-made inventions.

  • Hi, welcome to philosophy SE. It may have something to do with most people being right handed, etc., but that is a question of anthropology or psychology, not philosophy, see cogsci.stackexchange.com/questions Your question is also too speculative, we do not answer "what do you think" kinds of questions. Please visit our help center on asking philosophy.stackexchange.com/help/how-to-ask
    – Conifold
    Sep 6, 2016 at 7:06
  • It comes from numbering and writing habits. 1<2. Writing some times may be influenced from religious themes or practicality. (right hand is commonly stronger). When more advanced writing tools are available writing from left to right serves the practicality to start from close and move to the extreme. (and the ink drying issue) In piano low keys have lower frequencies. So in general we organize things in similar forms
    – John Am
    Sep 6, 2016 at 13:42
  • It's an arbitrary cultural choice. (but some right-handedness skews writing to left-to-right
    – Mitch
    Sep 6, 2016 at 14:09

2 Answers 2


Western writing systems - the Italic, Greek, and Cyrilic alphabets - are written left to right. It is usually supposed that this has a practical reason - when writing with ink, the right hand moves to the right without touching the still fresh ink of the recently written words. And most humans are right-handed, for reasons I ignore (and I suppose science ignores too, albeit this pseudo-scientific evil conspiracy called evolutionary psychology probably having its two cents of illogical and unfalsifiable pseudotheories about the issue).

But Arabic alphabet is written right to left, and it doesn't seem its users actually have a problem with messing the ink with their right hands. So it might be merely contingent; if you flip a coin, it will give you either head or tails, and there is no use to speculate on the "reasons" why it ended with tails up ex post facto.

Two of the issues you point - the order of years in timelines and the order of books in shelves - are directly related to the way we write. I do not know if timelines or shelves are organised differently in countries that use the Arabic alphabet, but it would be logical, and I suppose that if it is not the case, it is probably due to Western influence.

As for the order of the keys in a piano - and other keyboard musical instruments - it seems to follow from the fact that our musical tradition puts more emphasys in the higher voices(1). We hear the soprano, the violin, the flute conducting the main melody, while the baritone, the cello, or the bassoon, play a secondary role, providing harmonic support for the main voice. In a keyboard instrument, consequently, we are to expect that the higher notes will be melodic and involve more complicated hand movements, while the lower notes will provide harmonic support. As most pianists, organists, etc., are right-handed, it makes sence to put the lower note keys to the left.

(1) "Higher", here, in a merely acustic context, as in, "higher wave frequency", not implying any superiority.

  • Why such fury against evolution psychology? I'm not aware of the issues or the specific trend, but do you think psychology is not influenced by evolution?
    – John Am
    Sep 6, 2016 at 13:50

Regarding left/right, you can see the wotk of the French sociologist Robert Hertz (1881 – 1915) :

Death and The right hand (French ed. Prééminence de la main droite, 1909), page 89-on:

The preponderance of the right hand is obligatory, imposed by coercion, and guaranteed by sanctions: contrarily, a veritable prohibition weighs on the left hand and paralyses it. The difference in value and function between the two sides of our body possesses therefore in an extreme degree the characteristics of a social institution.

One fundamental opposition dominates the spiritual world of primitive men, that between the sacred and the profane. [...] Dualism, which is of the essence of primitive thought, dominates primitive social organisation.

All the oppositions presented by nature exhibit this fundamental dualism. Light and dark, day and night, east and south in opposition to west and north, represent in imagery and localise in space the two contrary classes of supernatural powers: on one side life shines forth and rises, on the other it descends and is extinguished.

The different way in which the collective consciousness envisages and values the right and the left appears clearly in language. There is a striking contrast in the words which in most Indo-European languages designate the two sides. [...] The same contrast appears if we consider the meaning of the words 'right' and 'left'. The former is used to express ideas of physical strength and 'dexterity', of intellectual 'rectitude' and good judgement, of 'uprightness' and moral integrity, of good fortune and beauty, of juridical norm; while the word 'left' evokes most of the ideas contrary to these.

Analysis of the characteristics of the right and the left, and the functions attributed to them, has confirmed the thesis of which deduction gave us a glimpse. The obligatory differentiation between the sides of the body is a particular case and a consequence of the dualism which is inherent in primitive thought. But the religious necessities which make the pre-eminence of one of the hands inevitable do not determine which of them will be preferred. How is it that the sacred side should invariably be the right and the profane the left?

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