The past is a different country

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The past misleads us into believing the world is solvable because the past is fixed, complete, all knowable information is known, there can be nothing unexpected. We know what happened .

When the data is in we can calculate, somehow the probability Lucy Letby there was a serial killer on the ward. Could we have predicted that in advance?

All data is from the past. It can do a tidy job of helping us fill in the gaps about the past by triangulation: we can make sensible Bayesian inferences to work out what must have happened even if we did not see it. But here the sample space is closed, the boundaries are known — these are conditions for probabilistic reasoning.

In the future, they are not. You cannot make expected value calculation about the unknown future in a complex system.

This, in a sense, is the unfairness of an referendum. We know about the status quo — it is from the past—: we know nothing about the alternative, which is in the future. We literally do not know what we are voting for. Full Brexit? EEA? Customs Union? Withdraw diplomatic missions?

See also

• The Bayesian
• Brexit means Brexit
• There is no data from the future
• Complexity