to infinitive- result or purpose?

[keannu]

It's sometimes really confusing to tell "result" and "purpose" of to-infinitive. I learned that when there is a verb denoting involuntary actions like "She grew up to be a super model" or "He lived to be 90", you can interprete the to-infinitive as "results".
But in the following, it seems either a result or a purpose. Don't native speakers care about the difference or do they have any standard to tell the two?

ma90)...When you chew something, a chemical goes to the nose. Then the smell and the taste go to the brain. So it is the taste mixed with the smell that the brain uses to tell different tastes. In other words, the nose and the taste buds work together to make your sense of taste.

[bhaisahab]

It's sometimes really confusing to tell "result" and "purpose" of to-infinitive. I learned that when there is a verb denoting involuntary actions like "She grew up to be a super model" or "He lived to be 90", you can interprete the to-infinitive as "results".
But in the following, it seems either a result or a purpose. Don't native speakers care about the difference or do they have any standard to tell the two?

ma90)...When you chew something, a chemical goes to the nose. Then the smell and the taste go to the brain. So it is the taste mixed with the smell that the brain uses to tell different tastes. In other words, the nose and the taste buds work together to make your sense of taste.

I would interprete it as a result. Most native speakers wouldn't care one way or the other.