At one time banks and post offices used to tie down the pen that they provided for people to sign things, such as cheques, with a piece of string or chain to prevent customers from stealing the pens. These days you are more likely to have a bunch of pens (with the bank’s logo) pressed on you.
Anyway, I was always discomforted by these tied down pens as I am left-handed and the string or chain was always fixed to the right of the counter and rarely was long enough for me to easily sign my cheques with left hand. As a result I was cramped up and twisted round as I manoeuvred the cheque book closer to the right hand side.
This is only one of the many times that my sinistralism has left me disadvantaged. Corkscrews and scissors, even power tools, wood screws and nuts and bolts are all designed for the majority who are right-handed. (I believe that the correct term would be dextralist). Can openers are the things that I find most tricky to use.
However, sinistralists living in a dextral world soon learn to use right handed tools, to at least some level of competence. There are tools made specifically for left-handed people and it is quite funny to give one to a right-hander. They don’t have a clue! This is because they have not had to learn to use tools with a sinistral configuration, whereas a sinistral has at least a level of competence with right-handed tools since they are everywhere.
The Universe obviously has a basic chirality or handedness which is a bit odd to say the least. It’s interesting to wonder why chirality exists. Is it just so that we can easily remove corks from bottles of wine? “Thanks, Deity, that just what we needed. Will you take a glass?”
Chirality makes it hard for some creatures. Imagine that you are a mollusc with a left-coiled shell and all the other mollusc are right-coiled. You’d find partners to be rare. Of course, it can’t make reproduction too difficult or the left-coiled molluscs would become extinct within a generation or so. (That’s probably too simplistic, but let’s not quibble).
Chirality allows us to have streams of traffic travelling both ways on a single road, but I’m sure that Deity would have considered that and arranged for some way that we could duplex our highways. Allowing a way for solid matter to inter-penetrate would be one, but perhaps “both directions” implies chirality anyway and in a non-chiral universe there would only ever be one way.
In some universes (and maybe in this one for all I know) there may be cases of even more complex situations. One reflection of a chiral object changes it into another object that can’t be superimposed on the original object. A second reflection does allow it to be superimposed on the original. Imagine a universe where three or more reflections are need to allow the superimposition! In that universe the motorways and autobahns would need at least three carriageways.
The spin of some sub-atomic particles has an interesting spin characteristic. The linked Wikipedia article says in one place:
However, if s is a half-integer, the values of m are also all half-integers, giving (−1)2m = −1 for all m, and hence upon rotation by 2π the state picks up a minus sign.
Rotation through 2π is a rotation through 360 degrees. So a particle with a spin of ½ turns into its mirror reflection on one full rotation. At least I think that’s what that means. Two full rotations and it is back to its original orientation (or at least, its original spin value).
In the macro world two reflections of an object create an image that can be superimposed on the original. That means that if you look at the reflection of your reflection you see yourself as others see you rather than your mirror image. You are so much more used to seeing your reflection that it can be difficult to comb your hair while looking at a doubly reflected image of yourself.
Chiral objects are not symmetrical. Reflections of symmetrical objects can be superimposed on the original object however (after being moved and turned). Symmetry and asymmetry are part of the fabric of the universe that we live in and I think that having both allows for much more complexity in our universe than would be possible in a universe without the symmetry/asymmetry dichotomy.
One of the great questions of philosophy is “Why does anything exist?” or “Why does something exist rather than nothing?” The real answer to this question is that no one knows and no one is likely to know. I suppose the Deity might if the Deity exists Itself. Given that the universe exists why is does it embody the concept of left and right? Again, no one knows or is likely to know, or so it appears at this time.
One reason may be that if asymmetry did not exist one could probably not travel from A to B. If one started from A to travel to B in a universe without symmetry and hence without asymmetry, and someone else was travelling in the opposite direction then to pass one another the two travellers would have to pass on one side or the other of the other traveller.
It seems to me that the concept of “side” implies the concepts of “left” and “right”. Asymmetry comes in because, to either traveller, one passes to the left or right of the oncoming traveller who passes to the right or left of you. Symmetry comes in because, to pass one another both traveller has to keep to their left or their right to successfully pass one another.
Of course, that is only true for our universe. It is conceivable that a universe could exist where symmetry and asymmetry do not exist, but it is a universe which we would, most likely, be unable to conceive of, except in the broadest terms.