as free will: Scientific analysis and criticism The scientific community rejects astrology as having no explanatory power for describing the universe, and considers it a pseudoscience. Scientific testing of astrology has been conducted, and no evidence has been found to support any of the premises or purported effects outlined in astrological traditions. There is no proposed mechanism of action by which the positions and motions of stars and planets could affect people and events on Earth that does not contradict basic and well understood aspects of biology and physics. Those who have faith in astrology have been characterised by scientists including Bart J. Bok as doing so "...in spite of the fact that there is no verified scientific basis for their beliefs, and indeed that there is strong evidence to the contrary". Confirmation bias is a form of cognitive bias, a psychological factor that contributes to belief in astrology. Astrology believers tend to selectively remember predictions that turn out to be true, and do not remember those that turn out false. Another, separate, form of confirmation bias also plays a role, where believers often fail to distinguish between messages that demonstrate special ability and those that do not. Thus there are two distinct forms of confirmation bias that are under study with respect to astrological belief. Demarcation Under the criterion of falsifiability, first proposed by the philosopher of science Karl Popper, astrology is a pseudoscience. Popper regarded astrology as "pseudo-empirical" in that "it appeals to observation and experiment," but "nevertheless does not come up to scientific standards." In contrast to scientific disciplines, astrology has not responded to falsification through experiment. In contrast to Popper, the philosopher Thomas Kuhn argued that it was not lack of falsifiability that makes astrology unscientific, but rather that the process and concepts of astrology are non-empirical. Kuhn thought that, though astrologers had, historically, made predictions that categorically failed, this in itself does not make astrology unscientific, nor do attempts by astrologers to explain away failures by claiming that creating a horoscope is very difficult. Rather, in Kuhn's eyes, astrology is not science because it was always more akin to medieval medicine; astrologers followed a sequence of rules and guidelines for a seemingly necessary field with known shortcomings, but they did no research because the fields are not amenable to research, and so "they had no puzzles to solve and therefore no science to practise." While