Some philosophers believe that such science-fiction thought experiments (like the Twin-Earth) should be examined carefully. They argue that when a thought experiment describes a state of affairs that is radically different from the actual one (or what we think it to be), our intuitions can become unreliable, and hence the philosophical conclusions drawn from them may also be unreliable. Daniel Dennett calls Twin Earth and other experiments like it "intuition pumps", as they are designed in such a way to allow the thinker to use their intuition to guide them through the problem. Some philosophers take the Twin-Earth thought experiment/intuition pump to engage faulty intuitions, and hence lead to faulty conclusions. Phil Hutchinson, for example, notes that a) if one looks at Putnam's own later criticisms of others (for example his criticisms of Jaegwon Kim in his book "The Threefold Cord") one finds that implicitly he criticises his own earlier self; and b) that the persuasive power of the Twin Earth thought experiment/intuition pump relies on our turning a blind eye to aspects of the experiment in order that it establish that which Putnam claims it to. In short, the thought experiment is set up in such a way that one's intuitions will be pumped in the desired direction.