There are many Chinese words whose pronunciation can be represented as "''chih''" in Chinese:
* 志 zhì, aspiration, will. The "will" is a fundamental concept in the philosophy of Mencius, leading authorities such as David Nivison to classify Mencius as a "voluntarist" philosopher. Mencius believes that humans have four fundamental "beginnings" or embryonic drives that can, if protected and properly nurtured, form the basis of a human being who has immense powers to retain his or her autonomy. Each individual's ''zhì'' chooses that person's course in life on the basis of the four fundamental ethical drives and on other factors such as the desire for food, water, and the fulfillment of other ordinary requirements of life.
* 智 zhì, wisdom. This "wisdom" is the name of one of Mencius's four virtues which grow from the above-mentioned four beginnings. It is the innate ability to distinguish right from wrong in the actions of other people. For instance, one will automatically see something wrong when a large and powerful person takes advantage of a weaker adult or a child and be motivated to rectify the situation.
* 質 zhí, substance. The ''Huai-nan-zi'', 3:1a/19, says:
Heaven falls as the formless. Fleeting, fluttering, penetrating, amorphous it is, and so it is called the Supreme Luminary. The dao begins in the Void Brightening. The Void Brightening produces the universe . The universe produces qi. Qi has bounds. The clear, yang was ethereal and so formed heaven. The heavy, turbid was congealed and impeded and so formed earth. The conjunction of the clear, yang was fluid and easy. The congelation of the heavy, turbid was strained and difficult. So heaven was formed first and earth was made fast later. The pervading essence of heaven and earth becomes yin and yang. The concentrated essences of yin and yang become the four seasons. The dispersed essences of the four seasons become the myriad creatures. The hot qi of yang in accumulating produces fire. The essence of the fire-qi becomes the sun. The cold qi of yin in accumulating produces water. The essence of the water-qi becomes the moon. The essences produced by coitus of the sun and moon become the stars and celestial markpoints .
The idea that there is a heavier fraction of ''qi'' seems to have originated with this passage. Similar ideas show up in the writing of Song dynasty philosopher, particularly Zhu Xi, and there this kind of "materialized lifebreath" is called ''zhí''. Zhu Xi uses the idea of "materialized lifebreath" to explain what we today would call the nature of a human being as opposed to the nature of that human being.