I thought I had solved the problem. Somehow, I thought that if I put the step stool up on a high shelf, I would keep Little Man from accessing forbidden territory around the house. Silly me. I obviously didn't do a good enough job of putting away the "step stools." If I had done a thorough job, I would have also put away all boxes, laundry baskets, pillows, large toys, and of course, the dog. These are really only a few of the things that Little Man can turn into a stool in order to reach high places.
Obviously, if he is resourceful enough to solve the problem of how to reach Mommy's scissors or Big Sister's special tea set, he is smart enough to understand limits. So, I've been starting with the kitchen chairs. They are to stay at the table, period. They aren't to be pushed around the kitchen in order to access light switches or the kitchen sink. So, tonight, after getting a few cute pictures of him being naughty, I told him no and put the chair back at the table.
Within five minutes, he dumped his collection of toy cars and trucks out of their basket and carried the basket to the kitchen sink. After getting a few cute pictures, I put him to bed. I do believe I have my work cut out for me.