 Like arguments, thought experiments can be criticized in different ways. Perhaps the set up is faulty; perhaps the conclusions drawn from the thought experiment are not justified. Similar criticisms can arise in real experiments. Counter thought experiments are perhaps another form of criticism. They do not target the premises or conclusions involved in a particular thought experiment but question the phenomenon, i.e. the non-propositional heart of an imagined scenario (see Brown 2007). For example, Daniel Dennett is convinced that Frank Jackson’s Mary thought experiment is poor evidence to oppose physicalism in philosophy of mind. In Jackson’s version, Mary, who knows everything physics and the neurosciences can possibly know about colours but grew up in a colourless environment (seeing only black, white and grey things), allegedly learns something new when she sees a red tomato for the first time. Now she knows what it is like to experience red. This is an argument for qualia as something over and above the physical. Instead of a red tomato, Dennett, in his version of the thought experiment, presents Mary with a bright blue banana. In his version of the story (which seems just as plausible as Jackson’s), Mary balks and says she is being tricked, since she knows that bananas are yellow, and this, says Mary, is a consequence of knowing everything physical about colour perception. Mary does not learn anything new when she sees coloured objects for the first time, so there is no case against physicalism after all. Jackson’s initial thought experiment was very persuasive, but Dennett’s was equally so, thus, undermining Jackson’s argument.