I’ve seen this quote a number of times recently:

The definition of insanity is doing the same thing over and over and expecting different results.

It is typically misattributed to Albert Einstein, but is probably from Rita Mae Brown.

The quote is often true, but is misleading. Sometimes you do the same thing several times and get different results. For example, in the lab I did my thesis research in, there are two experiments that I have run multiple times, producing different results from different runs. According to the available measurements the experiments were identical. That doesn’t mean I couldn’t detect differences with better resources (eg doi:10.1038/nnano.2006.95), but as far as I can tell, they were the same.

Another common case is using computers running Windows. Trying the same thing several times when it didn’t work the first may be insanity, but it is necessary. One problem last week is a good example: I helped get a Sony VAIO laptop working with a Mustek A3 scanner. The software would seem to install properly, but the scanner would give an error message. The scanner worked first try on a ThinkPad running Windows 7, but wouldn’t run on the VAIO with XP, even after updating and cleaning the system. Before returning the computer and scanner, I decided to do one more thing: I plugged the scanner into a different USB port and ran Mustek installer then the Microsoft Scanner and Camera Wizard. It worked. I plugged it into the third USB port and repeated the process. It worked. I tried the first port again. The scanner still worked. Repeating the installation steps had fixed the problem. It can be convincingly argued that using an OS where performing the same steps multiple times leads to different results is insanity, but that isn’t the point of the quote.

Not that there aren’t many times when Brown’s quote is accurate. If you want examples of trying the same thing over and over expecting different results, when everyone knows what will happen, just read the newspaper.