Anyone for Tennis?

An example of Knightian uncertainty?

Sam, a Norwegian statistician, and Gina, a Moldovian game-theorist, have just met on holiday and are playing tennis. Sam knows that in previous games Gina has taken 70% of the opportunities to ‘go to the net’, and out of 10 opportunities in their games far, has gone to the net 7 times.

What is the probability that Gina will go to the net at the next opportunity? (And what is your reasoning? You may consult my notes on probability.)

More, similar, puzzles here.

Dave Marsay

Harris’s Free Will

This is a review of reviews of Sam Harris’s Free Will. I haven’t read the actual book. (One of Harris’s supporters says that I have no choice but to read the book: but I am not so sure.) 

New Scientist

The New Scientist has a review which says:

“We either live in a deterministic universe where the future is set, or an indeterminate one where thoughts and actions happen at random. Neither is compatible with free will.”

But why are these the only options? Harris is quoted as saying:

“You can do what you decide to do, but you cannot decide what you will decide to do.”

But what, then, is the point? 


This is a sympathetic review. He quotes:

“Why didn’t I decide to drink a glass of juice (rather than water). The thought never occurred to me. Am I free to do that which does not occur to me to do? Of course not. And there is no way I can influence my desires–for what tools of influence would I use? Other desires? To say that I would have done otherwise had I wanted to is simply to say that I would have been in a different universe had I lived in a different universe.”

I would call such acts ‘habitual’ and often executed ‘on autopilot’, like much of driving. But does all of driving involve such ‘decisions’? Does all of life?

The next quote is:

“What I will do next, and why, remains, at bottom, a mystery–one that is fully determined by the prior state of the universe and the laws of nature (including the contributions of chance).”

This is certainly a wide-spread belief, but not one that I feel free to accept at face-value. Why? Is there any possibility of any kind of proof of this belief, or anything like it, or even a faintly convincing argument? It is stated that the actions of a person are determined by their atoms (presumable as configured into molecules etc.). But is this really true? 

Sam Harris

In his blog, Harris focusses on the ‘moral’ implications of free-will and the need for an ‘illusion of free-will’. But if we rely on a false belief, aren’t we motivated to be cynical about ‘scientific reason’? Or at least, Harris’s version of it? But do not the language and methods of science and Harris assume what Harris asserts, and thus aren’t science and Harris unable to prove their own assumptions?

See Also

An article on critical phenomena argues that they cannot be understood from a classical ‘scientific’ viewpoint, thus undermining Harris’ assertions, especially those quoted by the friendly atheist. Briefly, we are not just a mechanical assemblage of atoms.


Harris’s views seem reasonable for the type of ‘decisions’ that fill Harris’s ‘life’, and it does seem to be the case that the physical world leaves little space for free will. But there may be a critical difference between ‘little’ and ‘none’, a possibility that Harris appears preprogrammed not to address. But are the relatively automatable kinds of decisions that Harris considers all there is to his life? Is his life really like a computer simulation of life?


Geopolicratus suggests that populations with an agricultural heritage are more institutionalised than those with a nomad heritage. If so, then those with an agricultural heritage might well be more disposed to believe things that suggest that there is no free will, since the two kinds of lives call for quite different kinds of decision making. Plato’s Republic, anyone? 

Dave Marsay