A public lecture from a scientist adding to the conversation. What makes this lecture interesting is he is not disproving that alien life can exist, but instead trying to curb expectations because of the little data we have to back up claims. More importantly is the message that it is important for scientists to be care of biases when discussing this topic.
Given the size of the universe, asserting that we’re the only intelligent life in it is a ridiculous stance.
We don’t need to be the only one period in order to be “alone”, we just need to be the only one within a particular large region. If the probability of intelligence arising is low enough then that’s not unreasonable.
This is one of the first things addressed in the lecture.
And he discredits his own argument 20 minutes later.