Quote Originally Posted by KJ6BSO View Post
The Drake Equation is meaningless. Depending on how you choose the data, you can make it come out however you choose.
It's a starting point. It implies nothing, merely gives the parameters and was useful in changing the viewpoint of scientists and the general public to the idea that there could be other civilizations on other star systems. It changed the picture of aliens from Little Green Men from Mars and The Blob to Klingons and Starman. A quantum jump in thinking.

It has been modified and extrapolated into other, sometimes more useful functions.

As with anything, if you are a pessimist, you will get an abnormally low number of Sentient Civilizations in the galaxy.

If you are an optimist, you will get an abnormally high number of Sentient Civilizations in the galaxy.

The truth is in-between as with most things.

Now, the real question is, did a pessimist discover fire? If not, then he's unlikely to discover extra-terrestial civilizations also.