I've had the computer screen open for 30 minutes now.  Nothing.  And yet my head and heart are so full of the things...all the things, in modern phraseology.  Finally, I decided to take my own advice, the advice that I give to my writing students -- just write.  You can always change it later; after all, this is a digital world. I want to tell you all about something and I am struggling.  I suppose that is the nature of the topic.  No, it is not some earth-shattering, life-altering personal news...or is it?  Hmm...but my topic for today, the one that I cannot put down, is this: witness.  Being a…