to do what they will, so long as they harm no other, or society as a whole, is a generally accepted principle within free and democratic societies; criminalization of acts that others feel are immoral, but are not clearly proven to be harmful, is generally violative of that principle; although exceptions may—and do—apply. (For example, the simple possession of child pornography or engaging in animal cruelty is criminal, in most civilized nations; however, there is no direct victim (except the animal, whose rights are not cognizable by law); the reason for its criminalization is the "bad tendency" of these acts; persons who derive pleasure from acts such as these often have depraved desires—it can be inferred that people who abuse animals, rarely stop there—and that people who possess child pornography will seek more than just mere depictions.) There are questions of the victimlessness of such supposed "exception" crimes as well as criticisms of the validity of assuming "bad tendencies" though. One example of criticism of the idea of criminalizing cruelty to animals out of a bad tendency in the people who do it instead of animal suffering is that research on the ability of animals to suffer by studies of animal brains is often used to determine what animals should be covered by laws against cruelty to animals, as shown in controversies about extending such laws to fish and invertebrates in which animal brain studies (not forensic psychiatry on humans) are the main cited arguments both for and against criminalization. It is also pointed out that computer games with "cruelty" to virtual mammals are legal in most Western countries while cruelty to real mammals is not, again showing that it is inner animal suffering and not outer body language that is relevant regardless of whether or not animals are formally classified as victims in courts. The notion of cruelty to animals as a predictor of violence to other humans is also criticized for lacking consistency with the evolutionary notion of empathy being gradually extended from close relatives to more distant relatives according to which cruelty to other humans should predict cruelty to animals but not the other way, explaining the appearance of cruelty to animals being a risk factor for violence to humans as a result of criminal investigation spending more resources investigating people known to abuse animals for human violence while people with no history of animal abuse or