Charles Darwin's personal struggles, including the loss of loved ones and bouts of illness, profoundly shaped his scientific theories. His experiences led him to question traditional beliefs and seek understanding through observation and study. Darwin's voyage on the HMS Beagle exposed him to diverse ecosystems and species, which informed his theory of natural selection. His struggles with depression also fostered a greater empathy toward the fragility of life, influencing his views on evolution and humanity's place in the natural world.