replies The most obvious objection to Dennett is the intuition that it "matters" to us whether an object has an inner life or not. The claim is that we don't just imagine the intentional states of other people in order to predict their behaviour; the fact that they have thoughts and feelings just like we do is central to notions such as trust, friendship and love. The Blockhead argument proposes that someone, Jones, has a twin who is in fact not a person but a very sophisticated robot which looks and acts like Jones in every way, but who (it is claimed) somehow does not have any thoughts or feelings at all, just a chip which controls his behaviour; in other words, "the lights are on but no one's home". According to the intentional systems theory (IST), Jones and the robot have precisely the same beliefs and desires, but this is claimed to be false. The IST expert assigns the same mental states to Blockhead as he does to Jones, "whereas in fact [Blockhead] has not a thought in his head." Dennett has argued against this by denying the premise, on the basis that the robot is a philosophical zombie and therefore metaphysically impossible. In other words, if something acts in all ways conscious, it necessarily is, as consciousness is defined in terms of behavioral capacity, not ineffable qualia. Another objection attacks the premise that treating people as ideally rational creatures will yield the best predictions. Stephen Stich argues that people often have beliefs or desires which are irrational or bizarre, and IST doesn't allow us to say anything about these. If the person's "environmental niche" is examined closely enough, and the possibility of malfunction in their brain (which might affect their reasoning capacities) is looked into, it may be possible to formulate a predictive strategy specific to that person. Indeed this is what we often do when someone is behaving unpredictably — we look for the reasons why. In other words, we can only deal with irrationality by contrasting it against the background assumption of rationality. This development significantly undermines the claims of the intentional stance argument. The rationale behind the intentional stance is based on evolutionary theory, particularly the notion that the ability to make quick predictions of a system's behaviour based on what we think it might be thinking was an evolutionary adaptive advantage. The fact that