Were those who put their money in Madoff securities entirely innocent? Or, like Madoff, did they too allow their desire for more wealth to run wild? Was Madoff’s desire for extreme wealth that far off the curve of human variation? And if he was off, who or what do we blame? Could some quirky feature of Madoff’s genome, together with the brain states it orchestrates, have pushed him over the edge into a universe of unreasonable and even irrational desires? Does it matter that Madoff grew up in a world in which the rich get richer despite the direct or indirect harm caused to innocent others? Many have speculated answers to these questions, based on little or no evidence, and certainly no scientific evidence. But what matters most about case studies such as this is that they raise the kinds of questions that science can answer. What matters is that it is possible to run a Ponzi scheme. It is possible because there are humans like Madoff who are driven by the desire to accumulate great wealth, despite the personal risks and costs to others. It is possible because the world is populated by people who are willing to throw critical reasoning to the wind in the face of a tempting offer to make a huge amount of money. It is possible because people will take risks either without considering the potentially horrific consequences to innocent others, or by trivializing them. As far as we know, Madoff never intended to put his friends and family members in a state of financial ruin. As far as we know, many invested in his securities knowing that investments can fail. As far as we know, some must have been suspicious, at least for a while, about how their investments could consistently yield such over the top returns when nothing else has or seemingly could. Madoff is certainly to blame for creating a fraudulent investment opportunity, but so too are the many who trusted him without question, happy to make absurdly high returns. Did Madoff cause excessive harm? Yes. Were those