Both “so that” and “in order that” are subordinating conjunctions commonly used to express purposes. As per use, “so that” conjunction of purpose is more common but less formal than “in order that”. “In order that” is used for more firm and determined purpose. Apart from this, “so…that” correlative conjunction is also used to describe cause and effect relationship in regular expressions.
Hidden meaning = for what” ?
The hidden meaning of both is relatively same with varying degrees.in order that is more firm and determined. But, both answer question “for what”.
Rules for correct use
•Both are subordinating conjunctions.
•Unlike so that, in order that is commonly used at the beginning or in the middle of the sentence. Hence, it is more formal than so that.
• So that is often placed in the middle of the sentence and followed by subject and verb.
•As a complex sentence, comma is placed whenever such conjunctions are used at the beginning of the sentence. Otherwise, comma is omitted in case of middle of the sentence.
•Apart from conjunction, in order that is also used as a phrase at the beginning of the sentence.
• Usually, modal verbs are along these conjunctions.
Useful examples — for what?
•He exercises daily so that he could stay fit and healthy. ( so that follows subject and verb)
•I use fountain pen so that I improve my handwriting.
•She has decided to go by train so that she can take more luggage.
In all the examples, ‘so that” is used in the middle of the sentence. Therefore, there is no need for comma or any other punctuation marks. Moreover, it is avoided at the beginning of the sentence as well.
In order that — for more firm purpose
•He works very hard in order that he could offer better future for his family.
•In order that he could offer better future for his family, he works very hard.
•In order that she could stay slim and healthy, she maintains strict diet.
•She maintains strict diet in order that she could stay slim and healthy.
In order to — infinitive clause
Infinitive is also preferred to express purpose apart from “that”.
•She maintains strict diet in order to stay slim and healthy.
•In order to improve my handwriting, I use fountain pen.
So…that correlative conjunction
So… that correlative conjunction is used to describe cause and effect relationship.
As a conjunction of purpose, “so that” is used to introduce the reasons for doing something — purpose.
But, as a correlative conjunction, “so…that” is used to express relationship between cause and effect. “So” is used for cause and “that” describes effect.
Some useful examples of so… that
Here, “so” is used as an intensifiers for following effect.
•I am so tired that I cannot walk further.
•Underdeveloped countries are so poor that they cannot invest in green technology.
In this way, the formation, as well as meaning of so…that is different from subordinating conjunctions of purpose.