Truth is the enemy of choice. If something is absolutely true (or right or good), there is no valid alternative to it. There is no rational choice involved. The choice between good and evil, for example, is no more than rhetorical: the appearance of an alternative simply reinforces the rightness of the correct choice. There is meaningful choice only when the possibilities are more equivalent or ambiguous, like a choice between household detergents or how to dress for the occasion. Yet, in the opposite extreme, the alternatives can be so apparently equal that there is no objective reason to prefer one over the other. That was the dilemma facing Buridan’s famous Ass. With two perfectly identical bales of hay to choose between, and no way to make up its mind, the poor creature starved to death!

There are several morals in the story. For the sake of argument, the creature is presumed to rely crucially on a perceptible external difference to make a decision. Further, it should decide. A real creature’s hunger would naturally override any indecision. Human beings too are nominally smart enough not to be immobilized by indecision. Yet, we do rely heavily on alleged realities to determine our choices. Should one vote liberal or conservative if the parties’ platforms are scarcely distinguishable? Or should that redundancy discourage voting at all? Is there something corresponding to the donkey’s hunger that would drive citizens to vote despite a lack of meaningful choice? Though choice in the marketplace of consumer goods is similarly limited—and often meaningless—that hardly stops people from spending their hard-earned money.

At the extreme represented by absolute truth or value there is no real choice. Absolutes compel compliance. But at the extreme of no evident truth or value there is simply no basis for choice. If “free will” is a matter of choice, then it must lie somewhere between these extremes. But, of course, truth and value are not entirely external matters. To some extent (but which, exactly?), truth is in the eye of the beholder, and value is value to someone in particular. (The hay is of value to the donkey; one bale may loom larger in the moment of peak hunger.) Whether or not differences are objectively real, it is up to the subject to act (or not) upon differences perceived. Yet, the fundamental dilemma of a trade-off remains: freedom is conditional to the extent we rely upon externals (perceivable differences), while a rationale for choice is undermined to the extent that we ignore them. Determinism and free will are opposing human constructs—extreme idealizations. Between these extremes, where does instinct, intuition, or common sense lie in choosing, whether for the donkey or the human?

Here’s a thought experiment. Imagine a tube down which ball bearings roll in a vacuum. This tube is perfectly ideal, as are the perfectly fitting metal spheres, with perfectly identical dimensions. The tube is perfectly vertical. Below is situated a sharp wedge, perfectly centered underneath the tube. This wedge diverts the falling balls either to the left or right. We should expect a random distribution of balls going either way, analogous to the outcomes of random trials like the tossing of a coin. Any preference for one side or the other would indicate that the wedge is not perfectly centred (corresponding to a “loaded” coin if the statistics is not even between heads and tails). However, it is physically possible for a coin to land on its edge. Only an infinitely thin coin would totally exclude this unlikely possibility. Similarly, we could suppose the wedge is honed to infinite perfection and centering on the tube. As with the coin tosses, two infinitely ideal perfections are pitted against each other—like the irresistible force versus the immovable object. Perfect undecidability is pitted against the perfect means to decide. In this counterintuitive situation, instead of veering left or right, the perfectly elastic falling ball could hit the wedge square on and bounce right back up the tube! In the absence of disturbing forces, even the infinitely thin coin could balance on its razor edge. No decision is made. This is the sort of logical stalemate that idealization can produce.

Occam’s Razor is the principle that the simplest explanation should be preferred. It presumes a well-defined criterion of simplicity and a well-defined situation. To coin a term, Buridan’s Razor is the principle that a distinction can always be made on which to base a choice, if only one’s powers of discrimination are honed enough. That doesn’t mean that choosing is always necessary. Sometimes it’s handy to keep alternative explanations or options on hand. Nor is choosing always meaningful or desirable. Bales of hay are irrelevant to a satiated donkey—or to one that is currently falling to its death alongside them from a high cliff. On the other hand, in this cartoon situation, that momentary state of weightlessness wouldn’t preclude choosing, purely as an act of free will. The fact that we seem to have solid ground under our feet gives apparent weight to our choices. But are we not all falling through time?