There’s no void to fill it’s really just a philosophy that embraces the potentiality of technology to augment human form and society. If there is a void that people are looking for transhumanism to fill its the void in our life spans. I could easily do 400 years given how much rapid and radical change we are likely To see. It would be amazing to watch us build the first underwater cities and live in one, or live on a off planet colony. Or even contribute to building them.