I have a lot of trouble with that exact question. It's no wonder the concept of a 'soul' is so pervasive over the ages - it explains things so neatly. It's like there is a cosmic Kubernetes cluster and at birth a process gets randomly assigned to a CPU.
Yeah, it's called evolution. You are one bet in a pool of bets for future survival. A single, uninterrupted, open-ended process that created all life on this planet. How many of our creations can lead to such diversity in one single run?
