Subjectivity and rationality---主体性と合理性

Today I wrote a paper about the traditions of Subjectivity and Rationality in Western philosophical history, so I (watch your capitalisation - in casual writing it's no big issue, but for academic/formal writing you need to adhere to the rules very strictly!) will introduce its outline.

In Western philosophy, many philosophers tried to bind subjectivity and rationality when they mentioned the discussing the concept of truth. (stylistic improvement)

''Where'' can we find the truth? In Subjectivity, or Rationality? In English-language academic writing, rhetorical questions should be used more sparingly (less often).
If we lean to favour Subjectivity, it becomes difficult to share the truth. However, if we choose (chose is past tense) Rationality, simply the truth simply leaves us and it becomes an armchair theory.

I would put it this way: "If we favour Subjectivity as our framework, it then becomes difficult to exchange truth or meaning. However, if we lean towards Rationality, then truth and meaning leave our concrete human experience and become merely conceptual theories with no experiential significance on the individual level." I hope that is the idea that you wanted to convey!

In At the end of 18th century, Kant tried to bind them in a manner that I will call and I called it "The Marriage of Subjectivity and Rationality".
Although the accuracy of his thought his reasoning was accurate, the marriage was in a difficult situation and never be completed truly settled.

The repulsion arguments (repulsion is too strong a word) against Kant are mainly divided to two directions.

The first, one is analytic philosophy, lead by Bertrand Russel.
They abandoned subjectivity and mentioned championed the individuality of rationality and logic. However, clealy, it remains the problem of the direct relationship between human and truth still remained.

The second school/type/direction of counter-argument against Kant was Exitentialism lead by Kierkegaard who said ''truth is subjectivity''.

The insistence This position/argument/claim is very powerful, but dangerous, because it dosen't care in its disregard for rationality. 
However Without rationality, the truth becomes only an issue of each person and philosophy or dialogue becomes untenable. nonsense.

Then Consequently ('then' is fine, but consequently is more specific and sounds better!), I think we must sincerely considerate ('considerate' is an adjective) both, because the key to the truth needs the marriage of subjectivity and rationality, inspite of the lack of our ability our lack of ability to know whether or not the marriage can be sustained. 

Very good! A quick note regarding the use of "truth" vs "the truth".

"The truth" might presuppose that there is a single specific 'true' statement. E.g. "Did you hit your brother? Tell me the truth!".

"Truth" as I used it in this correction refers to the concept of truth, without necessarily insisting that there is a single true fact to be known. It is a very advanced use of English, but the difference between "the truth" and "truth" is important to philosophy, especially in a debate around subjectivity/objectivity/rationality!