Does popular belief determine truth or is it factually based?  I have always loved mathematics as it is indisputably factually.  Two plus two equals four.

Or does it.  Is the rule of math a human creation or a thing that is intrinsically true?  (In case you are wondering about this post it will be my new years first stab at deep philosophy, or is it the new decade?)

Therein Lies the Rub

Is the year twenty-twenty the first of a new decade or the last of a retiring decade?  I have read articles in the press welcoming the new decade.

Alternatively an internet search muddies the waters with definitive explanations of how 2020 is the first year of the decade and the last year of the decade.

There are references to the common calendar, the Julian and Georgian calendars and other perspectives as well.

Just Count It

For me, this is a mathematical problem which is entirely based on counting.  The issue arises relative to the rules associated with counting.

Simply put, if the number of things cannot include zero (a latter day concept invented by Greek mathematicians) than a decade starts with one and ends with ten.

By this logic, twenty-twenty is the tenth year and so the end, not the start of a decade.  (This logic of course presupposes full agreement that a decade consists of a count of ten, although I am sure someone will argue this)

On the Other Hand

If zero is a counting place holder, that is year zero counts than a decade runs from zero to nine and twenty-twenty is year zero and so the start of a decade.

So when does the new decade begin?  You can decide.  It seems it is a personal choice.