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“Family Time” the Genealogist’s Way

By Daniel Hubbard | May 27, 2012

Have you ever noticed how differently we perceive time? Every circumstance implies its own meanings for “a long time ago” and “recently.” Every human activity has different ways of measuring time. A cosmologist might consider a billion years to be a brief period. For a particle physicist a nanosecond (one billionth of a second) can be significant. When people refer to “geological time” they mean tens of millions of years. What would “genealogical time” be?

Genealogical Time

I often think of things occurring within “genealogical time” if they happened recently enough that it is reasonably possible for someone to trace their decent from an average person of that time. How long ago that is depends on the location. For parts of England that followed the law “genealogical time” by this reckoning probably starts with 1538 and the legally mandated keeping of parish registers. One can go back farther, but the degree of luck required increases and the amount of certainty drops while the difficulty rises.

It is always possible for people to migrate from a time and place that is within “genealogical time” to a place that is beyond it. They only moved from one place to another and yet measured by the continuous keeping of records that leads from then to now, they have moved backward in time, over a horizon beyond which it becomes unreasonable to try to follow them. Their descendants and their descendants’ descendants will, in all likelihood, remain unknown even if their ancestors were clear.

From Birth to Death

Another measure of genealogical time, is the human lifespan. Knowing human kind’s three score and ten years of life, making allowances for those few who lived an extra score and ten and knowing when a person was born we can estimate when someone might have been alive.  It also tells us how long memory might be living and when the living memory of an event was sure to be extinguished.

It takes remarkably few lifespans to bridge to long ago lives. Looking at my own pedigree, the lives of my own grandparents bridge back to the lives of their own grandparents, born in the 1840s. With any luck, I will live to see that bridge reach 200 years.


The most famous measure of genealogical time is the generation. It is a useful part of the genealogical concept of time. One generation as a measure of time fits the way genealogy works, much like people once measured the size of a piece of land not by its area in square feet or square miles but in terms of how many days it took to plow it. That might not tell you how much land you owned but it did tell you how much work the land represented. The generation is similarly fuzzy. On average it is about 30 years but in any one case it can be little more than a decade or, for a man, as much as an entire lifespan. It is a remarkably stretchable measure of time but useful nonetheless because it stretches to fit.

A generation in a paternal line will, on average be longer than on a maternal line but the difference need not be large. In six generations, my paternal and maternal lines differ by only seventeen years. Much larger differences are possible. There is the now famous case of the two living grandsons of President John Tyler, born 1790. A span of three lives covers 222 years and counting because the generations were extreme. President Tyler was 63 when his third to last child was born. That child was about 75 when his still living sons were born.

With generations that long, there is no chance to hear stories from grandparents. The generations themselves are long but the overlap of generations is minimal. I require only the lives of my grandparents to bridge back to my great-great-grandparents. In principle, I could have heard a story from the life of a great-great-grandfather from the mouth of someone who heard it from him—two storytellers from the 1840s to me. The president’s grandsons may have a grandfather born in 1790 but it would still take two storytellers, two memories, to reach back that far. Given that they are four decades older than I, the span of time covered by those two storytellers is almost the same. That brings me back to memory…


When nitrogen in the atmosphere is struck by cosmic rays, it can turn into carbon-14. Plants absorb the carbon-14 and it spreads into animals from there. After death, the carbon-14 is no longer replaced. It gradually vanishes from the remains of that once living thing by slowly decaying at a precise rate over thousands of years. By measuring the carbon in a sample of organic material, the time since it died can be estimated.

In a similar way, we subconsciously use memory as time’s gauge. Time is often measured by the quantity and quality of memory. Memories decay and family stories fade across generations. The clearer the memory, the more detail rich the story, the more recent it seems to be. There is a catch. Memories don’t fade at a precise rate like some sort of mental carbon-14. The more interesting a story, the better it is remembered and the more recent it will appear to be. As “memory time” shifts forward or backward against the calendar, stories and facts can move from one person to another. They migrate to the generation that the clarity or cloudiness of the story seems to imply. A tale from the distant past becomes a story about grandpa because it feels so clear and current. A murky childhood story from a parent shifts back into the time of grandparents or great-grandparents because it seems so nebulous.


Perhaps it is a common experience but there seems to have been a time in my childhood when people’s ages became frozen. My mother’s parents will always be in there seventies in my mind. They would be over 110 if they were still alive. Every adult I knew at the age of about ten became frozen in time in my memory. I know how old they are but each has an essence in my mind that dates from thirty plus years ago. How that will affect my stories, I do not know.

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