One of the central tenets of Aubrey de Grey’s SENS ideology is that if we can increase life expectancy by 1 year every year then we can be immortal.  If the increase in life expectancy is itself increasing incrementally year after year then we might be able to “pull out” of the death spiral similar to a plane using it’s afterburners to pull out of a nose dive. 

However, reality suggests that this improvement in life expectancy is far off in the future (if ever). 

According to data provided by the Center for Disease Control, the average 65 year old has a life expectancy of about 17 years, so he will live to 82 years on average.  The figure below shows the change in life expectancy for 65 year old white males over the 20th century.  Surprisingly, life expectancy has improved only about 5.5 years in the last 100 years. 

Most of the increase in life expectancy from birth (about 27 years from 48 to 75) came from reduction in infant mortality.  However, once you made it past about 10 years old, life expectancy improved only a few years in the 20th century, despite massive improvements in scientific knowledge and application. 

Looking at the figure, one can see that life expectancy for 65 year olds has been improving more rapidly starting from the 1970s.  However, before you get too excited, this improvement has been on average only about 40 days/year; well below the required 365 days/year necessary for immortality. 

What more, this trend seems pretty linear and not exponential so there is currently no reason to think it is accelerating. 

So based on the scientific evidence, the reasonable person should take Aubrey de Grey’s claims of immortality with a grain of salt.