Well, not really alone – God, angels, and demons exist – but when it comes to physically manifested intelligence, we – and any organic, cybernetic, and AI programs we are able to make – are all the minds that exist.
At least in an evolutionary universe.
The main reason is a natural consequences of the forces Ray Kurzweill discusses in The Law of Accelerating Returns.
In a nutshell, ever since the rise of the industrial era two hundred years ago, our technological abilities and our wealth has been expanding at an exponential pace. Quoting from his abstract:
An analysis of the history of technology shows that technological change is exponential, contrary to the common-sense “intuitive linear” view. So we won’t experience 100 years of progress in the 21st century — it will be more like 20,000 years of progress (at today’s rate). The “returns,” such as chip speed and cost-effectiveness, also increase exponentially. There’s even exponential growth in the rate of exponential growth. Within a few decades, machine intelligence will surpass human intelligence, leading to The Singularity — technological change so rapid and profound it represents a rupture in the fabric of human history. The implications include the merger of biological and nonbiological intelligence, immortal software-based humans, and ultra-high levels of intelligence that expand outward in the universe at the speed of light.
We are slated to get serious AI in fifty years or so, and we can already create life. We are well on our way to making Star Trek replicators under another name – 3D printers – and we can talk to anyone face to face around the world at a near-zero price.
If this was an evolutionary universe, with intelligences out there billions, or millions of years older than us, we would have certainly have met them by now.
We listen to the stars, and we get… nothing.
Now, if we live in a God-made universe – of which there is overwhelming evidence, thanks to the immense amount of information packed in our cells and etched in our environment, even to the very nature of the laws of physics – there is a possibility of a God-made non-human (or perhaps even human!) sophont race out there. And it is very likely we would not have met them, if the universe is less than 10,000 years old.
But that is not what the futile search for ET is about. It’s about proving evolutionary claims for the random generation of life.
If any such intelligence existed, they would have far surpassed our technological level by now, assuming evolutionary time scales.
There isn’t even a hint of evidence that such beings exist.
So, assuming that God didn’t make another sophont race out there – and there is no evidence He did, and plenty of circumstantial evidence that suggests that He didn’t…
…we are alone.
Until we ourselves lead the charge to bring life to all those dead worlds out there.