Suicide is selfish in the sense that it destroys the brain and body of the individual who suffers from its endless craving to possess pleasure and escape pain. The problem is that new bodies and brains are constantly being created at exponential rates. When I was born in 1936 there were just over 1 billion bodies with brains on this planet; now, in 2020 there are almost 8 billion. The planet cannot sustain life at that pace—not even viral life because viruses need hosts, multi-celled animals and plants to survive.
That’s the way the universe seems to be: billions of galaxies, stars, and planets appearing, creating space as they evolve at the speed of light and then collapsing back into nothingness in a “steady state,” as the astronomer Fred Hoyle speculated in the 1950s.
Yet, as Russell sensed, there should be a way for human life to live harmoniously with its planet to the end of its life span. He sensed it through his definition of philosophy in Autobiography as “definite knowledge,”—i.e. physics, chemistry, and biology. All three are now detailed beyond what the human intellect can understand. That is what is quite properly called the mystery of existence.
In Autobiography Russell gave special attention to William James’s “radical empiricism,” Epicurus, Spinoza, Neo-Platonism, and Plotinus. He recognized that science, “definite knowledge,” results in mystery. That fact was intuited by the earliest human beings whose brains reached the level of consciousness.