The universe is big. Very big. Infact, it's so big that us human beings find it absolutely mind boggling, that is; it's far too big for our minds to grasp. The Milky Way (Our galaxy) is 1000 light years deep and 100,000 light years wide comprising an estimated minimum of 200 Billion stars.
That's just one galaxy. The biggest problem is that you can bandy around 10,000 or 100,000 and we understand the numbers easily, some of us can even visualise those numbers, but who can visualise those numbers when they relate to light years and the equivalent distance? The answer is very few, if anyone can.
There's a famous case of a jungle dwelling people who had no concept of distance and therefore perspective, that is; objects look smaller the further away they are from the viewer. People who have only ever lived in an environment where they can only see 20ft cannot understand why a human being is not the same size as they are if they see a human 500 yards away.
The same is true of human beings with regard to how vast the galaxy is. We just cannot comprehend how big and how many stars are contained in our galaxy and then comprehend the probabilities of other "Earths" existing let alone other planets that could contain life that we would have absolutely no conception of. We can estimate mathematically, but we cannot comprehend the numbers.
Secondly we assume that life is just like that which we see and experience. Why? Why can't life be very different? Why do we assume that we are the norm? Perhaps we are the exception and other life forms, based on other chemistries, are the norm. What is special about us? Why is it that human beings always think that we are special because we cannot grasp the incredibly huge numbers? Human beings are naturally poor at statistical analysis, we tend to be anthropomorphous in our outlook and thinking, just like the OP.
To the OP - what is so special about the Earth and human beings?
There are an estimated 200 billion (200,000,000,000) stars in our galaxy. Even if 1% had a planet containing life that would be 2,000,000,000 stars. Lets say that 1% of that had intelligent life then that would leave 20,000,000 (20 million solar systems).
When we use tools such as the Hubble Space Telescope we can see deep into space. Regions that appear black and empty suddenly show, under examination, hundreds of galaxies. There are an estimated 125 Billion galaxies in the observable universe.
Even if we think of life as being extremely rare, the simple scale and numbers are so against us that any individual given the idea that;
a) we are not unique in our intelligence, b) there are an unimaginable and intangible number of stars and therefore solar systems that have the conditions to contain life exist, c) intelligent life amongst those is very rare but possible.
Is most likely to be right.
Why are human beings so special? Why do people think that the circumstances that arose on Earth could not produce us unless through intervention yet we have lower estimations of 200 Billion stars in our own galaxy and 125 Billion galaxies in our observable universe. We are most likely not special so why do some of act like we are?
