I had an experience at work today that nicely illustrates the faultiness of our memories.
Last week I was supposed to mail these letters, and I was 100% sure that I mailed them, there was no doubt in my mind. The people waiting for them had called a few times already and I told them yes I sent them. It was Wednesday afternoon, I was on my way out and I quickly packed them in the inter-office envelopes and popped them in the mail. I remember it so clearly as if I were doing it right now.
Finally today, after my boss asked me about them and I once again asserted that I did send them, I actually checked to make sure they weren’t still sitting on my desk. And lo and behold there they were. I could have checked easily the first time somebody asked if I had sent them, but my memory of sending them was so clear that I didn’t have an ounce of doubt.
I’m pretty sure that what actually happened was that it was the end of the day, I didn’t have time to address the letters, so I put them down on my desk to remind myself to send them the next morning. Somehow that mental note to remember to send them turned into a clear memory of popping them into the mail.
This is why eyewitness accounts of UFOs, hauntings, or anything for that matter are not to be taken as evidence. Our memories can be altered over time to the point where they no longer resemble what actually took place, even with something as mundane as mailing a letter.