I had to quit after 68 pages. Dennett apparently had a class of freshmen review this book - I wish he would have had a couple actual philosophers review it as well. If you have an understanding of philosophy and basic thinking tools, this book is not for you. If you already are an independent thinker, this book is not for you. If you are easily impressed by name-dropping and misleading examples, this book is for you.
The book starts out poorly with way too much name-dropping and Dennett admitting that he heckles lecturers for fun. He has very basic ideas of "thinking tools" and then uses very complex examples with very limited context. In these examples he takes cheap shots at fellow philosophers, while not providing enough context to really be able to agree that Dennett is in the right.
In chapter 1 he makes an innocuous yet unsound argument, and it is worth mentioning because it shows that he is very careless with his arguments throughout the book (or at least to page 68.) He states: "Evolution works the same way: all the dumb mistakes tend to be invisible, so all we see is a stupendous string of triumphs. For instance, the vast majority - way over 90 percent - of all the creatures that have ever lived died childless, but not a single one of your ancestors suffered that fate."
So...the majority of creatures don't pass on their genes. Dennett calls that an illustrative example of how ALL dumb mistakes are invisible (er..."tend to be invisible", whatever that means.) Who says that the 10 percent procreators aren't passing on dumb mistakes? Who says that sexual selection isn't selecting for "dumb mistakes" (ie. genes that make an animal more noticeable to predators, or genes that inhibit an animal to move swiftly.) His example is crude, and if the response is that "dumb mistakes" are ones that don't permit a creature to pass on its genes, then that just begs the question and proves nothing.
The above example was just a red flag. Things start to get really bad in Sections 13-15.
13. Dennett provides us an example where four characters all come, via different paths, to "believe that a Frenchman has committed murder in Trafalgar Square. He then adds that that proposition ("Frenchman committed murder in TS") does not occur to them. Thus they all have the belief without formulating the proposition. Dennett makes an implicit assumption here that you actually can have a belief without formulating a proposition. An implicit assumption that becomes a painful assumption when he drives his point home that people generally believe: "chairs are larger than shoes, that soup is liquid, that elephants don't fly." If I ask you if you believe that 44 plus 88 is 132, would you say yes? Had you ever formulated that proposition before? Isn't it quite likely that you believed the proposition only after the deduction? Thus, when someone witnesses Jacque shooting Bill, and Bill dying, the belief that a "murder" took place may not happen until post-deduction, that is, until the proposition is actually formed. Or when you're asked, "do elephants fly?" you first think of an elephant and then deduct that it can't fly? Dennett has not shown that I actually believe elephants don't fly without ever articulating the proposition one way or another.
14. "What this intuition pump shows is that nobody can have just one belief." Excuse me? Dennett, read a couple neuroscience books and then just take this section out. Even the pop psychology book Incognito should suffice. Even if Dennett's premises are sound (which at least one isn't), his conclusion isn't. His argument here is so poorly constructed I'm not even sure how to attack it. I think his argument goes like this: 1) Apparently inserting a false "belief" into Tom causes him to say something that he doesn't truly understand. 2) That shows that if we don't truly understand something, it isn't a true belief. 3) That shows that the only way to truly understand something is if it is coherent with other (sound) beliefs that one holds. 4) That shows that beliefs are thus supported by other beliefs. C) Therefore, "nobody can have just one belief."
I'm lost on how he got "beliefs MUST be supported by other beliefs" from the proposition "beliefs are supported by other beliefs." Also, I would re-write proposition 3 as "That shows that the only way to truly understand something is if it is NOT INCOHERENT with other (sound) beliefs." Stated this way, Dennett proves absolutely nothing and wasted 3 pages. I can have a single belief, and no other beliefs, and that single belief is not incoherent with any other belief. It pains me that Dennett is making money off of this book.
15. "Daddy is a doctor." This 1-page section did it in for me, I cannot continue this book. A little girl states the proposition "daddy is a doctor." 20 years later she makes the same proposition, only now she has a more sophisticated understanding of the words "daddy" and "doctor." Dennett writes, "If understanding comes in degrees, as this example shows, then belief, which depends on understanding, must come in degrees as well, even for such mundane propositions as this."
No! I am not convinced! A five-year old girl who utters the proposition "Daddy is a doctor" can have a full 100% belief in that proposition. 20 years later she can make the proposition, with a more sophisticated understanding, and still have a full 100% belief. Dennett, how does the 5-year old "fall short" of a full belief? Does she know that "daddy" refers to the person who tucks her in at night? Does she know that this person helps sick people in exchange for money? Then WHERE IS SHE FALLING SHORT?!!?!??! Maybe with other arguments not in his book, I could be convinced that I'm wrong and Dennett is right - but his one page argument is far from convincing and far from sound.
EDIT: I was so mad at Dennett that I didn't properly attack his argument. I will use an analogy: You have a lightbulb. At first, you can just turn a switch to turn the light on. But you get bored, and decide to make it more fun. You add a second mechanism - the switch needs to be flipped, and then you have to clap before the light goes on. You get bored again, and tweak it one more time: You have to turn the switch, then clap a specific pattern in order to turn the light on. No matter how sophisticated or complicated your INPUT might be, has absolutely no bearing on how sophisticated the OUTPUT might be. Any computer scientist or civil engineer could have told Dennett this.
Conclusion: I can't take any more poor logic from someone who is so pompous, name-drops relentlessly, and criticizes other philosophers without providing sufficient context for the reader to actually evaluate the criticism.