How Many Sentient Life Forms are in the Milky Way?

[NQ6U]

The Drake Equation is meaningless. Depending on how you choose the data, you can make it come out however you choose.

[N2NH]

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.

[n2ize]

The Drake Equation is meaningless. Depending on how you choose the data, you can make it come out however you choose.

In a purely mathematical sense it is correct because it's basically the "multiplication rule" for probabilities which is mathematically valid.. But that doesn't mean that the result obtained by plugging in values will be correct because most of the values that you plug in are themselves probabilities that are measured in terms of guesses rather than experiment. So, all in all the equation (at least for now) is a probabilistic measure of belief. The result is going to be subjective depending on the person applying the equation and whatever guesses they make for the probabilities.

As it stands now I would call the formula "mathematically valid" but not necessarily "scientifically valid". However, that may change over time if a more scientific means of experimentally determining the necessary probabilities Nonetheless, it is a cute formula to play around with in a dark room on a rainy night, provided of course that there is nothing else available to play around with in a dark room on a rainy night.

I would hardly say it has changed our view of the universe. However, science and astrophysics has and ironically as it does the Drake Equation may become more relevant as time goes by. On the other hand it may not.