by Douglas Hofstadter
Basic Books, 2007
p 43
It [the statistical outcome of flipping a coin] is a fact in its own right, at its own level. [...]
The higher level can blithely ignore the processes at the lower level. [...] No one really knew the slightest thing about atoms until only about a hundred years ago, and yet people got along perfectly well.
p 47
In November of 1993, I read several newspaper articles about a comet that was "slowly" making its way towards Jupiter. It was still some eight months from t-zero but astrophysicists had already predicted to the minute, if not to the second, when it would strike Jupiter, and where. This fact about some invisible comet that was billions of miles away from earth has already had enormous impacts on the surface of our planet [...]
p 106
Some integers are interesting. 0 is interesting because 0 times any number gives 0. 1 is interesting because 1 times any number leaves that number unchanged. 2 is interesting because it is the smallest even number, and 3 is interesting because it is the number of sides of the simplest two-dimensional polygon (a triangle). 4 is interesting because it is the first composite number. 5 is interesting because (among many other things) it is the number of regular polyhedra in three dimensions. 6 is interesting because it is three factorial (3x2x1) and also the triangular number of three (3+2+1). I could go on with this enumeration but you got the point. The question is, when do we run into the first uninteresting number? Perhaps it is 62? Or 1729? Well, no matter what it is, that is certainly an interesting property for a number to have!
p 172
[...] strange loops in mathematical logic have very surprising properties, including what appears to be a kind of upside-down causality. But this is by no means the first time in this book that we have encountered upside-down causality. [...] We concluded that evolution tailored human beings to be perceiving entities — entities that filter the world into macroscopic categories. We are consequently fated to describe what goes on about us, including what other people do and what we ourselves do, not in terms of the underlying particle physics [...], but in terms of such abstract and ill-defined high-level patterns as mothers and fathers, friends and lovers, grocery stores and checkout stands [...]
p 188
[...] are temperature and pressure real things, or are they just façons de parler?
p 324
In debates about consciousness, one of the most frequently asked questions goes something like this: "What is it about consciousness that helps us survive? [...]"
To ask this question is to make the tacit assumption that there could be brains of any desired level of complexity that are not conscious.
p 362
[...] we have, to take just one typical example, six billion trillion (that is six thousand million million million) copies of the hemoglobin molecule rushing about helter-skelter through our veins at all moments, and in each second of our lives, 400 trillion of them are destroyed while another 400 trillion are created.
May 2019