## Binary left shift

The logical (and arithmetic) binary left shift effectively doubles a number by moving the digits one position to the left, and inserting a zero in the least significant position. In practice the number of bits in a processor’s arithmetic register is fixed, so individual bits *fall off the left side* with each shift, and if you place a 1 at the least significant position then it will grow with each shift until it too falls off the left side. You can imagine this happening all at once, or just one bit at a time, though in the latter’s case you need to start the movement from the left towards the right or you’ll blitz the entire register. The rule is that old bits on the left need to move away first to make space for the small young ones on the right.

While this sounds like an introduction to binary mathematics, it’s actually a metaphor for a philosophical thought. My offspring lost both their grandmothers this year. Life’s register is short. Barely three generations. Four if you are lucky. There’s now nobody to our left. And the clock is ticking.

On the plus side, there are some interesting characters to the right…

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