and if he were to visit that former field , whatever its current condition as house or yard or parking lot or thicket , if he were to visit that field and find in it some trace of that which had entranced and enraptured and encased him in that one instant of that one day so long past , were he to be able to isolate that one bit of matter from that one day so long ago that had survived changed but the same till now , would it make any difference ?