ON THE ONTOLOGY OF HANDEDNESS

Handedness | Kant and Wittgenstein | Solution? | Or maybe not... | References

Handedness and philosophy

Handedness is a philosophical problem. It is a question about the distinction between 'left' and 'right'. How can one define these two concepts?

It seems to be impossible to define 'left' and 'right' without referring to any particular asymmetric object such as one's body or the Earth. One can just teach and say which one is which but one cannot define them. Hence, they are chiral concepts as 'clockwise' and 'north', too, for instance. Moreover, they are the most fundamental one since the other chiral concepts are understood only if 'left' and 'right' are understood. Understanding the difference between 'left' and 'right' is a basic requirement for being able to orientate in the world.

Kant and Wittgenstein

Two well-known philosophers who have taken part in the handedness discussion are Immanuel Kant (1724-1804) and Ludwig Wittgenstein (1889-1951).

Kant asks one to take a look at one's hands as examples. If you look your right hand in a mirror you see a left hand. And yet even though your hand is identical with its mirror image you cannot replace one with another. You cannot put right hands glove to your left hand (see Kant's Prolegomena §13).

Look at the image on the left. It is a two-dimensional illustration of two hands which are mirrored by a line, which is a one-dimensional object. In same manner, real three-dimensional hands are mirrored by a two-dimensional plane (such as a mirror on the wall). For instance, if you printed this page you would be able to cut either one of the hands out of the paper and move it on the other one by turning it around in three-dimensional space.

Ludwig Wittgenstein's answer to Kant was similar to that. He wrote: 'A right-hand glove could be put on the left hand, if it could be turned round in four-dimensional space' (Tractatus 6.36111). One just needs a one extra dimension. But is that a real solution? Doesn't Wittgenstein just move the problem to another dimension? For four-dimensional objects one needs a five-dimensional space, for five-dimensional ones a six-dimensional space, and so on, ad infinitum.

Solution?

Nevertheless, there is a way how to define 'right' and 'left' without referring to other chiral concepts or to particular asymmetric objects. The method was revealed by physicist Chien-Shiung Wu in 1958. You probably cannot, however, test it at home but below is the to-do list if you anyhow would like to know how she did it:

1. Cool the atoms of cobalt-60 to near absolute zero.
2. Line up their nuclear axes with a powerful magnetic field.
3. Count the numbers of electrons flung out by the two ends of the axes.
4. The end that flings out the most electrons is the end that we call 'south'.
5. It is now possible to label the ends of the magnetic axis of the field used for lining up the nuclei.
6. This in turn can be used for labeling the ends of a magnetic needle.
7. Put such a needle above a wire in which the current moves away from you.
8. The north pole of this needle will point in the direction we call 'left'.

What Wu did was that she demonstrated asymmetry in a physical phenomenon. Prior the her experiments, Wolfgang Pauli, a famous physicist, was sure that she would fail. He said: 'I do not believe that the Lord is a weak left-hander, and I am ready to bet a very high sum that the experiments will give symmetric results.'

I don't know how much Pauli lost but taken his premises, even God is a left-hander! But doesn't it sound so 'right-handed' to think that left-handedness somehow is more asymmetrical than right-handedness...

Or maybe not...

Physicists may now have peace in their mind: they succeeded to explain handedness. Still it is probably better to teach the difference between left and right to a child, for instance, by telling which hand is which one -- although they might find cooling of cobalt-60 atoms thrilling, too. Nevertheless, in our everyday world handedness has little to do with electrons flinging out of magnetic axes.

Below there are two photos of Hernesaarenkatu street in Helsinki, Finland (that is my home street). One is correct, another is a mirror image. Can you say which one is which?

If you look at the photos carefully you probably will be able to tell which one is which. Although the image is too small to read number of the licence plate you might know that driving in Finland is on the right side of the road. Hence, taken that most cars also use right side of the street for parking, it is the right side image which is correct.

However, if it was a nature photo -- a forest, for instance, it would have been much more difficult or even impossible to decide which one of the images was mirrored. They are cultural elements of the world that make us to recognize the difference. Hence, what ever physicists might say, question of 'left' and 'right' remains a cultural and not a natural phenomenon to us.

References

Gardner, Martin (1991). The Ozma problem and the fall of parity. In James Van Cleve & Robert E. Frederick (eds). The philosophy of right and left. Incongruent counterparts and the nature of space, pp. 75-95. Kluwer, Dordrecht.

Kant, Immanuel. Prolegomena : eli, Johdatus mihin tahansa metafysiikkaan, joka vastaisuudessa voi käydä tieteestä. 254 p. Gaudeamus, Helsinki.

Van Cleve, James (1991). Introduction to the arguments of 1770 and 1783. Teoksessa James Van Cleve & Robert E. Frederick (toim). The philosophy of right and left. Incongruent counterparts and the nature of space, ss. 15-26. Kluwer, Dordrecht.

Wittgenstein, Ludwig (1933/1996). Tractatus logico-philosophicus. 88 p. WSOY, Juva.

Apart from those books the following lecture course also has had remarkable influence on the content of this page::
Himanka, Juha (1999). Johdatus fenomenologiaan (Introduction to phenomenology). Lecture course, University of Helsinki, Department of Philosophy.

Updated Thursday, 18-Jan-2007 02:16:36 EET by NL