Leonardo DiCaprio has apparently made a new environmental film in the spirit of Al Gore's Inconvenient Truth, and as in the case of the latter, it seems some people have taken to dismissing the entire content of the film based on perceived hypocrisy of the film maker.

How did this happen in western thought, that if a person who makes a point is not a spotless example of that point, then it must naturally follow that his message is worthless? I see it used in arguments all the time. Maybe someone can explain it to me.

Because DiCaprio flew to Cannes in a gas-guzzling aeroplane (as opposed to the trans-atlantic train), he is a hypocrite and his message can be comfortably ignored as we all make our way home from the movie theatre speeding down the highway in our SUVs, content in the knowledge that the existence of hypocrisy must naturally cause the laws of physics to alter itself in such a way that the burning of fossil fuels no longer causes pollutants to rise into the air and threaten the very existence of our civilization -- perhaps even our species.

Or maybe its because if DiCaprio doesn't care about our world enough to find a non-aero based method of transport across the Atlantic, we are all relieved of our own duty to care about our world, and we can face the destruction of human society with the true solidarity of the apathetic?