Steve Pinker lists a good number of unsettling ideas (all ripe for research if you are brave enough):
Do women, on average, have a different profile of aptitudes and emotions than men?
Were the events in the Bible fictitious -- not just the miracles, but those involving kings and empires?
Has the state of the environment improved in the last 50 years?
Do most victims of sexual abuse suffer no lifelong damage?
Did Native Americans engage in genocide and despoil the landscape?
Do men have an innate tendency to rape?
Did the crime rate go down in the 1990s because two decades earlier poor women aborted children who would have been prone to violence?
Are suicide terrorists well-educated, mentally healthy and morally driven?
Would the incidence of rape go down if prostitution were legalized?
Do African-American men have higher levels of testosterone, on average, than white men?
Is morality just a product of the evolution of our brains, with no inherent reality?
Would society be better off if heroin and cocaine were legalized?
Is homosexuality the symptom of an infectious disease?
Would it be consistent with our moral principles to give parents the option of euthanizing newborns with birth defects that would consign them to a life of pain and disability?
Do parents have any effect on the character or intelligence of their children?
Have religions killed a greater proportion of people than Nazism?
Would damage from terrorism be reduced if the police could torture suspects in special circumstances?
Would Africa have a better chance of rising out of poverty if it hosted more polluting industries or accepted Europe's nuclear waste?
Is the average intelligence of Western nations declining because duller people are having more children than smarter people?
Would unwanted children be better off if there were a market in adoption rights, with babies going to the highest bidder?
Would lives be saved if we instituted a free market in organs for transplantation?
Should people have the right to clone themselves, or enhance the genetic traits of their children?
This essay was first posted at Edge (www.edge.org) and it is the Preface to the book 'What Is Your Dangerous Idea?: Today's Leading Thinkers on the Unthinkable,' published by HarperCollins.