Answer: He found that relying on nature was ineffective because not only were lightning strikes lighting fires relatively rare, they were inconsistent. Although the fires were watched very carefully because do early humans fire was very valuable, inevitably, as he wrote, they would be blown out, due to wind, rain, and various other factors. This could be extremely dangerous for early humans because not only did they use fire for food they use it for warmth and to ward away predators. So he understands that relying on nature is reckless and can lead to deadly consequences.
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