This is a common fallacy about evolution, and is explained beautifully by the anthropic principle, or in other words, the innate selection bias of our existence.
I'm a little confused about how the anthropic principle explains this fallacy (and it is a fallacy to be sure). I guess you're referring to how natural selection (and all the other sorts of selection that occur regularly) lead to the existence of "appropriate" organisms and features.
But I think knowing some of the actual details in how evolution works at all the different levels (molecular bio, epigenetics, competition/cooperation, behavior, etc, etc, etc) serves as an even better explanation. Here's a 25 lecture course from Stanford that explains just that: http://www.youtube.com/watch?v=NNnIGh9g6fA
Absolutely, but Penrose was a brilliant man; he surely understood the biological and scientific explanations of it all. Yet, he still held some mysterious belief that there was something magical about the process. This belief comes from the self-selection bias (http://en.wikipedia.org/wiki/Self-selection_bias) (NOTE: not natural selection or evolutionary selection; there's a conflict of terms between probability theory and biology there—sorry for the confusion) I spoke of, and many people share it. From our individual perspective, or even from a human-wide perspective (which are the ones most familiar to all of us) we appear extremely special, extremely lucky to exist at all; to have been in the right place at the right time to undergo this process of evolution.
The anthropic principle simply invalidates this mystery: it is not special, it simply happened, and because it happened, we exist to observe it.
It doesn't care to explain evolution in any biological or scientific way; it only seeks to remove all doubt that it was able to happen at all.
I'm going to take a few seconds here to be a pedant and disentangle the structure of an argument from its contents.
Strictly speaking, a fallacy is a defect in the structure of an argument, i.e. in the logic that connects a premise to a conclusion. What you and the parent have identified is simply a false premise ("Things at least seem to organize themselves somewhat better than they 'ought' to"[1]). A false premise may result in the wrong conclusion, but an argument can be wrong without being fallacious.
This distinction isn't so much relevant here, but it comes in handy when you want to pinpoint sources of disagreement in a discussion. Lobbing the f-word around (even when deserved) just makes people defensive.
1. Of course the argument used to derive this premise might be fallacious, but that argument isn't given.
Thanks for making the distinction, but the word "fallacy" can also be used more loosely than the way you define it. Googling "fallacy definition" gives me:
1. A mistaken belief, esp. one based on unsound argument.
2. A failure in reasoning that renders an argument invalid.
I'm a little confused about how the anthropic principle explains this fallacy (and it is a fallacy to be sure). I guess you're referring to how natural selection (and all the other sorts of selection that occur regularly) lead to the existence of "appropriate" organisms and features.
But I think knowing some of the actual details in how evolution works at all the different levels (molecular bio, epigenetics, competition/cooperation, behavior, etc, etc, etc) serves as an even better explanation. Here's a 25 lecture course from Stanford that explains just that: http://www.youtube.com/watch?v=NNnIGh9g6fA