I catch the subway at Penn Station, NY, to visit a neuroscientist friend before heading back home to Brazil, my hands occupied trying to keep the suitcases upright, my head distracted, floating from one loose thought to the next - when I notice the dark blue tiles on the wall of a station: 59th street. The association is immediate and inevitable, and The 59th Street Bridge Song springs readily to mind, two voices, guitar and all:
"Slow down, you move too fast/we've got to make the morning last/just kicking down the cobblestones/looking for fun and feeling groovy..."
I've known this song by heart since my teenage years, when most of my English vocabulary came from Simon & Garfunkel songs (and Agatha Christie's crime novels; I had a most peculiar vocabulary). So I sing the cheery words of the song all the way uptown, from Queensboro to my destination, on 168th Street - where any remains of the song are driven away from my mind by more prosaic going-ons regarding how to negotiate subway doors and hallways while carrying two suitcases, a handbag, and a case of brains (yes, primate brains, from Jon Kaas's lab, where I had been the previous weeks) all by myself. The subject at hand is, all of a sudden, an entirely different matter.
As William James would put it, the thoughts that occupy our conscious mind follow one another constinuously, like the stream of a river, without interruptions. Some stem from within, from our own internal processes, desires, memories, and projections for the future; but here and there some external stimulus bursts in, and for some instants draws the stream of thought to itself, bringing to surface the memories and emotions associated with it - like the joy that surfaces along with the words to the 59th Street Bridge Song. And so, hopping from association to association, with my stream of thought occasionally interrupted by this or that chance event, by my own memories, and by those pertaining to my currrent target, on Haven Avenue, I arrive at my destination. The mind wanders around, but it keeps its course.