The first thought experiment Dennett uses to demonstrate that qualia lacks the listed necessary properties for it to exist involves inverted qualia. The inverted qualia case concerns two people who could have different qualia and yet have all the same external physical behavior. But now the qualia supporter might then present an “intrapersonal” variation. Suppose a devious neurosurgeon fiddles with your brain and you wake up to discover that the grass looks red. Wouldn't this be a case where we could confirm the reality of qualia— by noticing how the qualia have changed while every other aspect of our conscious experience remains the same? Not quite, Dennett replies via the next intuition pump, “alternative neuro-surgery.” In fact there are two different ways the neurosurgeon might have accomplished the inversion above. First, she might have tinkered with something “early on,” so that the signals coming from the eye when you look at grass contain the information “red” rather than “green.” This would result in a genuine qualia inversion.But, alternatively, she might have instead tinkered with your memory. Here your qualia would remain the same, but your memory would be altered so that your current green experience would contradict your earlier memories of grass. Note, you would still feel that “the color of grass has changed”; only here it isn't the qualia that has changed, but your memories.But now, would you be able to tell which of these scenarios is correct? No: your perceptual experience tells you that something has changed but not whether your qualia have changed. Dennett concludes, since (by hypothesis) the two different surgical invasions can produce exactly the same introspective effects while only one operation inverts the qualia, nothing in the subject's experience can favor one of the hypothesis over the other. So unless he seeks outside help, the state of his own qualia must be as unknowable to him as the state of anyone else's qualia. This is hardly the privileged access or immediate acquaintance or direct apprehension the friends of qualia had supposed qualia to enjoy! It's questionable, in short, that we have direct, infallible access to our conscious experience.