How does Buridan’s Ass decide?

Wednesday, February 25th 2015

I have often said in these pages that I have difficulty making up my mind when I have to choose between two or more similar things. For example, suppose I go into a shop to buy a new pair of trousers and am presented with two pairs. Let’s say that both fit me perfectly, both cost the same and I like both of them but there are slight differences between them. Which shall I choose?

In such circumstances, I find myself in what we might call a state of elective inertia or, if you prefer, I can’t make up my mind.

This is the situation that the 14th-century philosopher Jean Buridan studied and illustrated with an imaginary scenario that has come down to us as Buridan’s Ass. (The problem in fact already occurs in Aristotle but we needn’t let that detain us apart from acknowledging the Greek philosopher’s primacy.) Buridan imagines an ass, or donkey, standing equidistant from two piles of hay. The piles are the same size and the hay in both is equally fresh and tasty. The donkey therefore cannot make up his mind which pile to eat and therefore dies of hunger.

Now, of course, Buridan’s ass isn’t a real donkey. He is an imaginary entity, like Schrodinger’s cat, dreamed up to illustrate a paradox. In real life, donkeys don’t die of starvation in the presence of piles of hay. Similarly, I am confident that I will eventually emerge from the shop carrying my new pair of trousers. But if neither the donkey nor I can make up our minds which hay or which trousers to go for, how do we reach a solution to the dilemma?

All this hinges, of course, on the question of free will. Philosophers have argued throughout long centuries as to whether human beings (and perhaps also donkeys) possess free will. The problem is not made any easier by the difficulty of defining exactly what we mean by free will. What is it, do I have it and how can you tell?

Suppose we are out and about and decide to go for coffee. Looking around, we see a pair of coffee bars side by side. Each belongs to a well known chain so we know what to expect in each. “Shall we go to coffee bar A or to coffee bar B?” asks Tigger. “You decide.” I reflect and then say “On previous occasions when we went to B, the coffee was weak and tepid and altogether not very good, whereas the coffee in A has always been excellent. Let’s go to A.”

Did I use my free will in choosing A over B? I might have done, for all that any of us knows, but it wouldn’t have been necessary. There is clear and sufficient reason for choosing A rather than B. In the modern parlance, “It’s a no-brainer”.

Now suppose that in fact we like both coffee bar A and coffee bar B equally and have always found the coffee, the service and the surroundings excellent in both. Which shall I choose then?

To tell you the truth, I will find it difficult. I will hum and ha, shuffle my feet, try to persuade Tigger to choose but in the end I will make a decision. How?

If you say “By exercising your free will”, you are not answering the question in any meaningful way. I will simply ask you “How did I, exercising my free will, make up my mind?” Postulating free will doesn’t explain how we make choices. Therefore, the fact that we do make choices does not imply that we possess free will.

Let’s suppose we invent a robot with an electronic brain. Its job is to negotiate a maze. Every time it reaches an intersection, it has to choose whether to go left or right. Because we are not very clever at artificial intelligence, we program the robot to choose by generating a random number. If the number is odd, the robot goes left and if the number is even, the robot goes right. We can say that the robot is making a choice but we can’t say that it has free will because it is entirely constrained by its programming which is purely deterministic. (Even generating a random number is deterministic because it is performed by a fixed algorithm. We may not know what the outcome will be but once it has occurred, we can in principle explain why.)

So, when I choose one of the coffee bars over the other, am I exercising free will or am I merely responding to some deterministic process? Putting this another way, in the presence of two options of which neither has a clear advantage (or disadvantage) over the other, how do I nevertheless make a choice?

There is a principle which most philosophers and scientists adhere to, and to which I too in my humble way also adhere, and is expressed in the neat little Latin tag: Nihil sine ratione, which means “Nothing (happens) without a reason”. Looking at it another way, it is an expression of the well founded belief that everything that happens in the universe is the result of chains of cause and effect.

If this is right, and I cannot imagine that it could possibly not be right, then whenever I make a choice, there is a reason for my choice whether I recognize this or not. Worse still, if I can still make a choice in the absence of a clear and sufficient reason for doing so, how can I be sure that what I think is my clear and sufficient reason for a choice really is not merely a fantasy explanation dreamed to reassure myself that I have made a free and rational choice? I would argue that I can never be absolutely sure about that.

If I can never be absolutely sure about my reasons for making a choice, where does that leave free will? If my choice is not the result of conscious ratiocination, then it is the result of hidden causes of which I am unaware, like the robot in the maze responding to the random number generator.

I would argue that my (and the donkey’s) situation is a little better than that of the robot, but only a little. There will be all sorts of impulses milling about in my brain, of which I am for the most part totally unaware (except when they pop up in dreams, Freudian slips, etc), and when I need to make a choice, I may find myself pulled this way and that by contrary impulses. Eventually, this storm somehow resolves itself and a choice emerges. I think I have “made” the choice, and in a sense I have, but I haven’t made it in the clear and conscious way I think I have.

Does this mean we have no free will but are merely driven by an unconscious that continually argues with itself? I think that depends on how we define free will. If we take it to mean that we have the freedom to act when we are not constrained or coerced by forces external to us (such as moral and legal laws), then yes, we have free will. If, on the other hand, we take it to mean that we are free to act according to conscious choices arrived at through balancing lists of pros and cons, then no, I don’t think we have free will in that sense. I think our choices are always mediated by impulses that are partly or even completely obscure to us.

Copyright © 2015 SilverTiger,, All rights reserved.


About SilverTiger

I live in Islington with my partner, "Tigger". I blog about our life and our travels, using my own photos for illustration.
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8 Responses to How does Buridan’s Ass decide?

  1. BFG says:

    It took me a while to decide that I don’t believe there is any thing such as free will. I come at this from the perspective of a belief in a cause and effect universe, so it’s a logical conclusion, not one based on superior knowledge 🙂

    Ergo, no matter which decision one makes, it was pre-ordained (for want of a better term). I am perfectly happy with that but I don’t expect anyone else to be.

    I know there is a school of thought that uses the weirdness of the quantum world as evidence that the universe is not cause and effect. My feeling is that they are missing a piece of the puzzle, and by that I do not mean a Supreme Being, but rather one or more dimensions of time and/or space.

    The effect known as Quantum Entanglement (spooky action at a distance, as Einstein is reported to have called it) can be explained by the presence of another, hidden, dimension connecting the objects that have become entangled (and they don’t have to be atomic particles apparently). The Grandfather Paradox (which arises when contemplating time travel) can be avoided by positing at least one more dimension for Time and thus avoid the possibility of the universe becoming trapped in an infinite loop as a result of some antisocial activity aimed at your Grandad when he was a whippersnapper.

    Since our universe is already so mind-bogglingly huge I don’t have a problem with contemplating the possibility that it might be only one of some 10^500 possible universes (the Multiverse theory) – or that it came into existence out of nothing, if it isn’t. (One aspect of the Multiverse Theory posits that our universe came into existence when two Branes briefly collided.)

    Of course, none of this helps you make a decision. But it passes the time while you’re waiting for your mind to make up itself 🙂

    • SilverTiger says:

      I have heard that some cosmologists think the universe is 11-dimensional, which gives it plenty of room to play about in. There is undoubtedly a lot more to learn about it and how matter behaves at the lower limits. In that connection, the blog Gravity and Levity might interest you.

      Assuming a cause-and-effect world, one of the things that intrigues me is the existence of minds that, as well as being aware of their surroundings, are also aware of themselves and aware of being aware of themselves. It also intrigues me that if there is no free will we can still conceive of the concept. Or that we can indeed conceive of fiction at all.

      I do not see any reason to suspect the existence of a Higher, let alone Superior, Being. In fact, I would say that the evidence firmly points in the opposite direction.

  2. WOL says:

    To me one does not have free will if one does not have a choice. Choice implies a freedom to choose. I’m not a hair splitter. It doesn’t really matter to me whether my choice is actually free or not. (and what criteria determines a “truly free” choice anyway?) If it seems free to me, then as far as I’m concerned, it is. I’m pretty uncomplicated that way. My BFF on the other hand hyperanalyzes and second guesses herself to an astonishing degree. I make the best choice I can according to my lights, and go from there. I don’t reanalyze unless the circumstances change in some way.

    • SilverTiger says:

      One can indeed envisage various degrees of freedom of will. For example, suppose one is locked in a cell in which there are two chairs. One is free to choose to sit in either chair but not to sit in a chair outside the cell. As long as one is content with the choice of two chairs, one can say with Hamlet “I could be bounded in a nutshell and count myself a king of infinite space”.

  3. Keith Nichols says:

    If a number of things are of equal attraction, there is no question of free will, because one of them is the same as any of them. Grab the nearest to hand and be on your way with no dithering. Our problem is that even though the items seem the same, we fear they will prove to be different in some way that makes our selection unfortunate.

    • SilverTiger says:

      If there is nothing to choose between the possibilities then, on the face of it, this is where free will might come in, in order to “force” a choice. It is interesting to see what people do in such a situation. The exression commonly heard is “flip a coin”, and I think this is what people do, whether using an actual coin or a virtual one. When I eventually “make up my mind”, there will be a reason for my choice even though I may be unaware what this is.

      The other interesting point is the fear you mention: because we can speculate, we tend to do so for all our possible choices and then, whichever we choose, worry than another choice would have worked out better. Since we cannot follow two separate timelines, we can never know whether another choice would have worked out better and this leaves the mind free to speculate.

      • Keith Nichols says:

        It seems there are few significant choices we make among truly equal candidates. For example, if a business executive is picking one from among a few job applicants whose qualifications for a position are equal, he ends up breaking the tie based on factors not directly related to the job and not on the job application form. These factors may be how the candidates combed their hair or whether they wore bow ties, and other emotional criteria. What part of all this is due to free will?

        • SilverTiger says:

          Arguably none. In order to use an extraneous decider such as hairstyle, gender, accent, etc, these have first to occur to him. In other words, he has the choose the additional criteria, bringing us back to the original question.

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