Franklin reverses the traditional promise of the philosopher’s stone, a legendary substance believed capable of turning base metals into gold. He says he has never seen such a transformation succeed, but has seen people lose genuine wealth while pursuing it. The contrast turns alchemy into an example of how belief in extraordinary rewards can lead to very ordinary financial losses.

The broader point concerns judgement, credulity and speculation. A person attracted by the prospect of effortless or exceptional gain may spend money, time and attention on an idea without sufficient evidence that it can succeed. Franklin is not rejecting experimentation or ambitious projects in general. His warning is directed at pursuits whose promises are far stronger than the evidence supporting them. The saying therefore encourages scepticism towards schemes that offer remarkable rewards while placing existing resources at risk.