The elimination of reason would be the elimination of humanity. From Jeff Thomas at internationalman.com:

Recently, I paid for an item with the exact amount requested, including 89 cents in change. The salesgirl stared at the coins and clearly wasn’t sure what to do. Eventually, she reached for a calculator and began to total them up one at a time: 25 + 25 + 25 + 10 + 4. Having been schooled in the age prior to calculators, I’m accustomed to doing arithmetic in my head, but this particular instance evidenced a level of “dumbing down” over the last fifty years that was beyond what I had realised.
Since the dumbing down has been so consistently prevalent over the decades, it’s clear that this is no accident, nor is it an experiment in “alternative education” that hasn’t worked out as was intended. It’s clearly the result of a conscious effort to diminish the average person’s ability to think. As such, it’s had a long gestation period and was expected to require generations, but was nevertheless a conscious goal.
But why on earth would the controlling elite of any country seek to diminish the power to reason? Surely, reason is the basis of all independent thought – the catalyst for new ideas and improvement on existing goods and systems.
The answer, in a word, is control. Independent thought is the prime enemy of those who seek to dominate a people. For that reason, those who rule will happily sacrifice technological and social progress if it means that their dominance can be increased.