Say we have 3 people: A, B and C. A has a ball in their hand but B and C don't. The following occurs:

A, gives their ball to B,

then B, gives their ball to C.

Now if I ask you the question; Why does C have a ball? or What is the reason that C has a ball?

What is the answer? Is it because A gave the ball to B in the first place? Is it just because B gave the ball to C? Is it because I, the author of this question, made the scenario this way so it's because of determinism? Is it something else entirely or all of these at once?

  • 3
    And because the Earth exists and A, B, C are alive, "why X?" is a badly ambiguous question. There is a multitude of "reasons" or "causes" that can be offered as an answer, and they are classified by multiple factors. For example, proximate and ultimate causes, material, formal, efficient, and final causes, etc. In everyday situations the context sometimes disambiguates what is meant. If not, people ask "what do you mean?" questions.
    – Conifold
    Commented Jul 19, 2022 at 17:47
  • 2
    This is the famous Principle of sufficient reason employed as early as Anaximander, Parmenides, Archimedes of pre-Socrate Greek philosophers and made prominent by Leibniz, and per Aristotle there're 4 types of such sufficient causes and your description belongs to efficient (agent) cause... Commented Jul 19, 2022 at 19:26
  • 1
    Does there have to be just one answer?
    – haxor789
    Commented Jul 20, 2022 at 17:09
  • 1
    I would give Conifold's answer a thumbs-up if it were in the answer section.
    – BillOnne
    Commented Jul 21, 2022 at 20:35
  • Dependent Origination.
    – Scott Rowe
    Commented Jul 24, 2022 at 14:09

2 Answers 2


'Reasons' are features of our mental models of the world - they're not features of the real world.

Human minds build an internal simulation of the world around them, the mental model consists of 'objects' and 'agents', and 'arrangements' and 'relationships' by which they're organised, and 'rules' and 'laws' constraining how these entities change and transform. (I'm not saying this is a complete list.) We can start with an initial state of the world, and a set of causal laws and events, and use the model to predict the sequence of subsequent states. Or we can start with a final state, and reconstruct what events lead up to it. (Either to deduce what happened, or to try to figure out how to make it happen.)

'Reasons' are the chain of model manipulations we applied to get to a particular conclusion. They depend on the specifics of the mental model, and what we're trying to do with it.

So if we're using the model to predict the outcome state of a particular sequence of actions applied to an initial state, then the chain of actions and the relevant bits of the initial state are the reasons for the final state being what it is. The reason for C having the ball at the end is the initial state (A had it) and the two ball-passing actions. Other events not in this causal chain (like D having an apple and D eating it) are not reasons.

But if we instead were playing a game, and trying to figure out what chain of actions from the starting position we could take to win, then the 'reason' C has the ball is that C is closest to the goal, and A passing to B and B passing to C are consequences we introduce to make it happen. What is the 'reason' A passed the ball to B? A passed the ball to B, so that B could pass the ball to C, so that C could throw it in the goal and win the game. The 'x is the reason for y' relationship links them in reverse temporal order, because that's the way we're running the mental model.

Or we could start with both initial and final states, and be trying to figure out how we got from one to the other, maybe to figure out who to blame for the ball smashing the window. A must bave passed the ball to B because C was out of range, and there was nobody else on the basket court. Now the 'reasons' are in both past and future simultaneously.

'Reasons' are the steps in a proof. We start with axioms and assumptions, and proceed step by step to conclusions. We have a choice whether to consider only the immediately preceding steps as the 'reasons' for a particular conclusion, or the entire chain leading up to it. I don't think either choice is better or more widely accepted in everyday usage than the other. Again, it probably depends on what you are trying to do, and which is more convenient at the time.

Humans often get their mental model of the world around them and the world itself mixed up. We build a simplified mental picture of 'objects' and 'agents' and 'causes/effects' like toy building blocks we stick together in various ways, to try to understand and predict an infinitely complex world, and then we start questioning which of them are real. We invent 'paradoxes' where a particular kind of mental model we use to simplify the world doesn't quite fit, and suggest that it is reality that has somehow got it wrong, or is being especially mysterious in its inner workings. But we're wired that way. Building a mental model of it it how we perceive the world - to us, what we perceive is the world - and the abstraction step needed to separate them is not automatic.


Why does C have a ball?

Because the ball was transferred to C, and henceforth C retained it. Indeed, neither C gave the ball to someone else, nor was it taken away from C, nor did C lose/destroy it.

Note that that reason is not a tautology. It addresses the question by resorting to, or reflecting, the described sequence of events.

Conifold's comment lists a few types of causes, but I disagree that the question "Why does C have a ball?" is badly ambiguous. In the absence of terms that would narrow down the question, an answer premised on the efficient cause (see Double Knot's comment) is enough for enhancing the asker's knowledge, does not require speculating on elements such as the asker's mind, and does not suppress the context provided.

By contrast, the answer "because [...] the author of this question made the scenario this way" trivializes the matter insofar as it can be applied to any and all inquiries about the story and consequently purports that the story itself is entirely irrelevant.

Answering on the basis of other types of causes, such as final cause, would require information that in this instance is not ascertainable.

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