You are sitting at front of house with warm tea. Right when you drinking it with glass, there is vehicle accident at street of front house.

If you didn't drink it at that time before, will the accident still occur?

How you guarantee it would occured or not?

What if it will really not occured due to entanglement particles between glass and the vehicle in quantum level therefore there's butterfly effect in it that affect classic physic? But I can't guarantee it will not occured.

This question simmilar like post hoc ergo propter hoc fallacy except my question is contain negation.

So this makes me wonder if butterfly effect always happening.

  • Maybe your cup reflected the sun and momentarily distracted the driver. It's unclear how much effect your tea drinking had on the situation.
    – Wyck
    Oct 14, 2022 at 19:15
  • How you measure how much an effect? Oct 14, 2022 at 19:16
  • Yes. But.. 'Are things "caused" by the butterfly effect actually caused by them?' philosophy.stackexchange.com/questions/93931/… But causal is more a way of narrating & grouping experience, than something fundamental 'Is the idea of a causal chain physical (or even scientific)?' philosophy.stackexchange.com/questions/70930/…
    – CriglCragl
    Oct 14, 2022 at 19:17
  • 3
    I don't see how you could argue against the idea of the butterfly effect: that small changes in pre-conditions can have drastic effects on the outcome. It's mathematically demonstrable as chaos. All signs point to even macroscopic physical phenomena being susceptible to chaos (e.g. weather). But it usually takes time for small changes to have their large effect. (e.g. the weather does not change instantly in the case of the butterfly effect, but your teacup may be directly causally connected to a car accident via distracting the driver - rather immediately even)
    – Wyck
    Oct 14, 2022 at 19:22
  • 1
    If you think you find a case of real causality from empirical observation, experiment and laborious studies, just re-read Hume's famous problem of induction... Oct 15, 2022 at 4:01

4 Answers 4


You are sitting at front of house with warm tea. Right when you drinking it with glass, there is vehicle accident at street of front house. If you didn't drink it at that time before, will the accident still occur?

There is a difference between cause and coincidence and popular notion of the butterfly effect makes it easy to misinterpret. Just because an earthquake started when I turned on my vacuum cleaner is no reason to believe the vacuum cleaner is special or that the planet is sensitively dependent on the states of my vacuum. Not all behavior is acutely sensitive to initial conditions and the butterfly effect is not instantaneous. So while the butterfly effect may be going on all the time it's not something you will see and say Aha!


The "butterfly effect" or "chaos" is the following statement:

"Certain non-linear systems have a very sensitive dependence on (precision of) initial conditions, so that two identical systems with a slight mismatch (of the precision) of their initial conditions tend to diverge exponentially as they evolve though time".

This is the accurate statement of the butterfly effect.

In effect this means that the weather, as an example of such a non-linear system, when predicted over very long periods of time, needs almost infinite precision of the initial conditions to be fed to the simulator in order for the prediction to be accurate. Else the prediction can be accurate only for a short time interval depending on precision of initial conditions used. Thus if during measuring the initial conditions to feed the simulator, some small perturbations are left out (eg the movement of the wings of some butterfly), then the simulator over long period of simulation will exponentially diverge in its prediction from the actual system. However this is only over sufficiently long periods of time. For adequately short periods of time, the results of the prediction will not be very far off the actual outcome, and this is indeed how weather prediction works.

In other words, no, you lifting the glass and a car accident happening at that time is not related to any butterfly effect as explained above. Trying to find correlations (which do not necessarily imply causation) among events is a process that has pitfalls and one can easily land on "superstition land" if one does not validate the conclusions.


What’s the butterfly effect? Some things are very sensitive to initial conditions, for example weather. The slightest change (like a butterfly flapping its wings) will propagate and get amplified. A storm in four weeks time might not have happened if that butterfly had not flapped its wings. On the other hand, some storm that didn’t happen have happened in four weeks time if it hadn’t flapped. Weather is deterministic but chaotic, you can’t predict it.

No, you drinking tea didn’t influence the car crash. Unless you are in a habit of drinking tea while nude, clearly visible from the street, and attractive. Even in that case, drinking tea didn’t make the change.

Traffic tends to be more stable than weather. Most of the time it doesn’t affect you. A crazy driver on your street? Most likely not involved with you and not affecting you at all.


There seems to be a great deal of confusion in the minds of the general populace. That being that they think the statement:

"A butterfly flapping its wings in Beijing can cause a thunderstorm in Paris"

implies that every small action causes some major event elsewhere.

In realty, the vast, vast, majority of small events have no individual effect whatsoever at any scale above their own.

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