You ' re on the right track . Mutation rates are in fact under selection . However , it tends to be quite weak selection , so it ' s only effective in very large populations , and is only evident over large evolutionary time scales . There ' s therefore few studies that have been able to look at whether there is an optimum mutation rate to evolve to , since the timescales it would change over also include vast changes to environment , metabolic rates , etc . , which all cause mutation rates to change naturally . <| sep |> Can you give me examples ? In the meantime , I have some for you Conservatives don ' t want to pay to take care of homeless people , despite knowing that they cost between $ 40 k and $ 250 k per year in crime and healthcare costs . Compared to the $ 20 k it would take to cover them bigger government . Conservatives don ' t want a single payer healthcare system , despite knowing that it costs half as much in taxes as what we currently have . Bigger government . Conservatives are fine with military spending at WWII levels when we aren ' t even at war . Bigger government . Conservatives were fine with us going to war in the first place , for literally no good reason , lie after lie after lie , excused . Bigger government . Conservatives are fine with dictating whether we can use drugs , birth control , abortions , euthanization , etc . Bigger government .