The average human has an incredible memory. A simple sniff might trigger a reminiscence dating back decades. Perhaps of your mother setting a hot apple pie on the window sill to let it cool. We learnt about memory tricks during school. Memorizing large quantities of data to regurgitate on exam day. Eventually, later in life, our memory fades. Fewer details appear. Instead our memory provides vague stimulation to goodness and pleasure.

Then along comes computers. Computers keep our memories. Vast quantities of childhood photographs and videos. No longer do we need memorize data. It gets thrown at our eyes by the megabyte-full. Some is online. One video storage service has over 216,000 years worth of video. Some is off-line. In your personal computer. Totaling both these amounts comes to over 5 zettabytes; that’s 21 zeros. We don’t need our memories anymore. We can use computer storage to revisit any time from our past. Nothing will fade from our memories.

Do we need all these memories? Let’s consider. Not so long ago, in hunter gatherer days, humans had an average life expectancy of 33 years. At that age we were still learning; there wasn’t much to forget. Lifestyles improved and we quickly achieved longer lives. Now, the world average life expectancy is about 72 years. Many places, with high GDPs, have values above 80 years. And higher GDP means greater technology. Technology that places a commensurate higher demand on energy to create storage media, to record data and to replay. Over and over again. To what avail have we replaced our biological memory?