He does naught but bury himself in his books without any contact with the outside world. I'm afraid his theses will be so wishful so as to lack any connection to actual society.
Members of the committee are now having a closed session.
Examples (Wiktionary)
Mandarin
闭门谢客
閉門謝客
bì mén xiè kè
to close one’s door to visitors
Mandarin
在中国男篮败在希腊队脚下后，姚明并没有发火，而是中肯地提出了自己的意见，他说：“闭门造车打国内的联赛永远都是这样，必须让他们出去打比赛，不是一个一个队的出去，而是一个一个队员的出去，杀入外面每一个队。这样，我们的篮球整体水准才有可能提升。”
在中國男籃敗在希臘隊腳下後，姚明並沒有發火，而是中肯地提出了自己的意見，他説：“閉門造車打國內的聯賽永遠都是這樣，必須讓他們出去打比賽，不是一個一個隊的出去，而是一個一個隊員的出去，殺入外面每一個隊。這樣，我們的籃球整體水準才有可能提升。”
zài zhōng guó nán lán bài zài xī là duì jiǎo xià hòu ， yáo míng bìng méi yǒu fā huǒ ， ér shì zhōng kěn dì tí chū le zì jǐ de yì jiàn ， tā shuō ： “ bì mén zào chē dǎ guó nèi de lián sài yǒng yuǎn dōu shì zhè yàng ， bì xū ràng tā men chū qù dǎ bǐ sài ， bù shì yī ge yī ge duì de chū qù ， ér shì yī ge yī ge duì yuán de chū qù ， shā rù wài miàn měi yī ge duì ． zhè yàng ， wǒ men de lán qiú zhěng tǐ shuǐ zhǔn cái yǒu kě néng tí shēng ． ”
After the men's basketball team for China lost at the hands of Greece, Yao Ming did not become angry. Instead, he offered his own opinion, which cut right to the heart of the matter, "It will always be like this if we operate in a vacuum, and are forever only playing local league games in our own country. We need to let them go abroad to compete. It's not about individual teams going abroad. Rather, it's about individual team members going abroad and fighting their way onto the teams of other countries. That's the only way we'll be able raise the level of our basketball as a whole.