4 Reasons why there are no biological aliens visitors.

1. Technological progress is instantaneous in the scale of history. Once computers are developed their capacity to advance technology is practically exponential. Immediately biological beings augment themselves with these capabilities in stages, integrating them into their bodies to achieve immortality and self-design.

2. We look out into the galaxy and greater universe for signs of aliens, as biological entities in the "habitable" zones of solar systems. But what is a habitable zone? Habitable for humans? The entire universe is habitable if all you need is a solar source of power to build your robot bodies and store your mental data.

3. Population density is limited for biological beings, but for virtual computer based beings it is basically unlimited. It could exist on an ice planet for superconducting. It could be a continent printed by robots in space that simply travels and replenishes its energy from star to star.

4. Unless faster than light travel is possible, then a biological alien would either be a bored immortal traveling for hundreds of thousands of years to reach a "civilization" that may not even be there when they arrive or have to sleep. It's better to simply send out self-replicating robots in all directions that build a data infrastructure as they travel and send back data.

Proven beyond doubt.