If you're a scientist, and you have to have an answer, even in the absence of data, you're not going to be a good scientist.

The only accounting we had of the origins and the structure of nature was Biblical Genesis.

Relativity. Gravity. Quantum. Electrodynamics. Evolution. Each of these theories is true, whether or not you believe in them.

The word smart is not applied to all professions, even if you are smart in that profession. No one talks about smart lawyers. They may say a brilliant lawyer. They'll talk about a creative artist. Smart is saved for scientists. It just is. It's not even really applied to medical doctors. It applies to scientists in the lab figuring out what hadn't been figured out before.

For all we know, the aliens have already done this and unwittingly concluded that there was no intelligent life on Earth. They would now be looking elsewhere. A more humbling possibility would be if aliens had become aware of the technologically proficient species that now inhabits Earth, yet they had drawn the same conclusion.

The cosmic calendar is quite a fertile mode for communicating how small we are over time and space.

Intelligent life can't be all that common because it's really rare on Earth and especially since we define ourselves to be intelligent. But in the eyes of an alien coming here who has the technology to make it here, they might observe us and conclude that there's no sign of intelligent life on Earth.