Design & random chance

My design class is providing exercises to aid in stimulating new designs. Some of these techniques have been great; I've learned by doing. But others seem to me to reflect the exaultation of random chance. Perhaps it has to do with influence evolution theories have had in the many other disciplines including art.

I find myself with dubious expectations of best results based these controlled random chance exercises. Didn't Aaron's story to Moses run something along this line: I put the gold in the furnace and out came this golden calf? Well, it seems to me that the controlling part of the chance exercises are the best hope I have of any specatular results. I would welcome others' thoughts on these type of exercises. Have you encounter them? What were the results? How much control did you exercise over "chance" to get the results? Did you feel like you were bringing harmony out of disorder when you made adjustments? Or were you giving chance a helping hand? Do you see a difference between the insertion of chance into a design compared adding spontaneity?