Future

There are at least two reasons why we do not know the future. One is lack of information, and the other is instability. Even if everything we can know about something is known, still it is possible that very small changes in the conditions can change the outcome in a big way. That is what I call instability.
Seymour Hersh tells us today that Syria, Israel, North Korea, and the US, are withholding information on the attack late last year by Israel on Syria.

In that case somebody knows.

On the other hand Patrick Geryl claims that there is not much we can do to stop the Sun from bathing us in 2012 with a beam of electrons and protons. That event in turn will reverse the polarity of the magnetic field of the Earth, and kill most of us in the process.

Because of both types of situations, we do not know the future.