Chemical Term as Metaphor, II

Systematic Absences: In the crystal lattice, molecules, and therefore atoms, occur in a periodic arrangement, that is, a repeatable pattern. Similar to an Escher painting except in three dimensions. If you took Grade 11 physics, then you maybe did an experiment with a phenomenon known as diffraction, where you put small slits in a piece of paper and then looked at the diffraction pattern when you shone light through the slits. Depending on the pattern of slits, you would see a unique pattern of light and dark bars. Diffraction occurs where the light waves are scattered but interfere with each other after passing through the slit(s), so that some waves reinforce each other (a bright bar) and others cancel each other out (a dark bar, or no light). The same thing happens when you fire X-rays at a crystal, you get some resultant light and dark spots (remember now we deal in 3-D however, so things aren't so simple and you need the right computer programs to deconvolute the patterns. Remember also that people used to do this by hand up until about the early 80's when computing power improved.) The places where we would expect to see light spots but don't, are called systematic absences and they occur due to inherent symmetry within the crystal. The one thing you must keep in mind is that sometimes that inherent symmetry isn't there; not that the molecules are randomly arranged, because that would result in an amorphous solid and not a crystal, but that there is no higher symmetry than that of the simple repeat of the molecule within the crystal. In that case, there are no systematic absences. If we see them, then there is more symmetry than the simplest case. Wikipedia helps out a little bit, here, and here. Otherwise, use Google to find out about diffraction patterns and simple diffraction.

My email address for this site is systematic.absences (at) gmail (etc. etc.) I did not choose this moniker randomly, but took into account the fact that a great deal of my personal belief system is based upon inherent symmetry and as a result, finding things where you expect them (or the corollary: not finding things where you don't expect them). Like most people, I'm not a simple arrangement of molecules, and my thought processes are complex and often conflicting. No doubt you consider yourself similarly: your feelings and thoughts may be in direct conflict with each other, and you spend a great deal of time trying to sort everything out to keep a shiny veneer so that you won't appear to be completely barking mad. There are times therefore, when you do not behave as expected because too many things have cancelled each other out: your sister-in-law dies, and then your brother-in-law looks like his stomach cancer might have returned (to be confirmed this week) and your other brother-in-law has just gone for a liver biopsy to confirm a blood test. So you dig the garden, even though you should be cleaning the house because BF2 will be here in a few hours. You go outside and sit in the sun, and don't even bother with the garden because it will take care of itself anyway, it's good and strong. Then you notice that the garden is starting to die out, that summer has disappeared out from under your hospitalization and your sister-in-law's hospitalization and death, and cleaning out her condo, and visiting family and confirming that your father will die sooner rather than later, and looking at the mountains and lakes but not getting the usual regeneration from that, and school starts next week so summer is about done, as is the garden, so what's the point anyway?

Your sudden absence from the work or from where you're expected is just due to the cancellation of the diffracted information. And still, you plug on, just in the dark for a while. Overall, is there a patten? Overall, I believe that yes, there is. I don't know what it is because I obviously don't have all the data, but I believe that it exists. Does it take away from my notion of free will? Absolutely not. Do I feel as though everything is predetermined and that therefore my action or inaction has no bearing on the outcome of humanity? No, because that would be self-defeating and pointless. I hold both conflicting views at the same time: that there is an inherent symmetry, and that I determine my path by the choices I make.

Regardless of whether this view holds true for you, and quite possibly it absolutely doesn't, it holds for me and helps me understand how the world works. Some people don't need any kind of explanation, because for them the world just carries on and things happen without any rhyme or reason. There's nothing wrong with that outlook either, but it doesn't work for me.