# The Non-Reducibility & Scientific Explanation Problem

Q: What is a multiple star system?

A: More than one star in a non-reducible mutual relationship spinning around each other.

Q: How did it begin?

A: Well, I guess, the stars were out in space and at some point they became close in proximity.  Then their gravitations caused each other to alter their course and become intertwined.

Q: How did the gravitations cause the courses of the stars to become intertwined?  Gravity does one thing: it changes the shape of space-time; it does not intertwine things.

A: That seems right.  It is not only the gravities that cause this to happen.  It is both the trajectory and mass (gravity) of the stars in relation to each other that caused them to form a multiple star system.

Q: Saying that it is both the trajectories and the masses in relation to each other is not an answer.  That is what is in need of being explained.

A: You are asking the impossible.  I have already said that the relation is non-reducible.  I am not going to go back upon my word in order to reduce the relation into some other relation to explain it to you.  The best that can be done is to describe it as best we can.

Here is the problem: If you have a non-reducible relation (e.g., a 3-body problem or a logical mutual interdependence) then you cannot explain how it came to exist.  Explaining such things would mean that the relation was reducible.  But being unable to explain some scientific phenomenon violates the principle of science: we should be able to explain physical phenomenon.  Then the relation must not be non-reducible or it must have been a preexisting condition going all the way back to the origin of the universe.  Either you have a contradiction or it is unexplainable by definition.

What can we do?  You can hold out for a solution to the 3-body-problem or, alternatively, you can change what counts as explanation.  The latter option is the way to go, though, I am not going into this now.

For now I just want to illustrate that this problem of non-reducibility and explanation is pervasive:

Q: What is a biological symbiotic relationship?

A: More than one organism living in a non-reducible relationship together.

Q: How did it begin?

A: Well, I guess, the organisms were out in nature and at some point they became close in proximity.  Then their features caused each other to alter their evolution and become intertwined.

Q: How did the features cause the courses of their evolution to become intertwined?  Physical features do one thing: they enable an organism to reproduce; they do not intertwine things.

A: That seems right.  It is not only the features that cause this to happen.  It is both the ecosystem and the features of the organisms in relation to each other that caused them to form a symbiosis.

Q: Saying that it is both the place the organisms are living in and their features in relation to each other is not an answer.  That is what is in need of being explained.

A: You are asking the impossible.  I have already said that the relation is non-reducible.  I am not going to go back upon my word in order to reduce the relation into some other relation to explain it to you.  The best that can be done is to describe it as best we can.

As you can see, I am drawing a parallel between a multiple body problem and multiple organisms that live together.  Like the star example above, there is no way to explain the origins of organisms living together.  Even in the most basic case it is impossible.