Identity is such a difficult concept to grasp, particularly for our political leaders. They seek the magic device that will correctly distinguish "terrorist" from "tourist" or "refugee" from "freeloader." Unfortunately, what they're seeking is some measure of trust - "can I trust the motives of this person?"

So, here"s my first pop-quiz. What do identity and trust have in common? The answer - not very much.

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Most identities are defined in terms of the perceptions of others: for instance, we might buy the newspaper every morning at a kiosk before boarding the train to work. The vendor knows us by sight and says 'hello' every morning. That is an identity; it is self-contained and complete within the bounds of the interaction. Similarly, our 'family' identity is most strongly defined in terms of the perceptions of those around us. You might also consider the driver's licence as a self-contained identity.

Interestingly, although both are valid descriptions of 'you,' there is minimal overlap between the kiosk 'you' and the family 'you,' unless perhaps your spouse accompanies you to the city one day; and none at all between kiosk and drivers licence (apart from the photo on your licence).

The great thing about identity is that we have so many of them to choose from - not for any 'nefarious' purpose, but we intentionally partition ourselves into multiple 'people.' The 'David Heath' at work is quite distinct from the David Heath at home, for instance. At a simpler level, the identity we use when we visit some website that requires authentication has very little in common with anything truthful about us. But it is still an identity of ours.

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