Classical grammar words in the Dao De Jing
故 gù
In the Dao De Jing, 故 (gù) is almost always the conjunction “therefore, so” (61 times); once it is a noun, “the reason” (1).
故 is one of the book's commonest words. At the head of a clause it is a conjunction that draws a conclusion, “therefore, so”: 故能长生 (chapter 7), “Thus they can live long.” As a noun it means “cause, reason”.
Modern Chinese says 所以 or 因此 for the conjunction, though formal writing still uses 故. The noun lives on in 缘故 “reason”, and 故意 means “on purpose”.
故 as “therefore”
Pattern cause, 故 + result
A conjunction at the start of a clause: what follows results from what came before. It can open a new step of the argument, as in 故去彼取此 (chapters 12, 38 and 72), “Thus he lets go of that, and takes up this”, or join cause and effect inside one line: 不自见故明 (chapter 22), “Does not show himself, and therefore is apparent.” After 夫唯 “precisely because” or 以其 “because”, it gives the result: 夫唯不争，故天下莫能与之争 (chapter 22), “He does not contend, therefore the world cannot contend with him.”
61 times in 59 lines.
故常无欲，以观其妙，
Therefore, ever desireless, one can see the cosmos' mystery,
Chapter 1, line 5故有无相生，难易相成，
Therefore presence and absence produce each other. Difficulty and ease bring about each other.
Chapter 2, line 3故能长生。
Thus they can live long.
Chapter 7, line 4故能成其私。
This is precisely the cause of his fulfillment.
Chapter 7, line 8故几于道。
thus is almost like the Way.
Chapter 8, line 4故无尤。
it is beyond reproach.
Chapter 8, line 9
Show 53 more lines
故有之以为利，
Therefore, presence brings benefits,
Chapter 11, line 9故去彼取此。
Thus he lets go of that, and takes up this.
Chapter 12, line 7故贵以身为天下，
Consequently, one who values his body as he values the world
Chapter 13, line 11此三者不可致诘，故混而为一。
These three ultimately cannot be fathomed. Therefore they join to become one.
Chapter 14, line 4夫唯不可识，故强为之容。
Precisely because they cannot be known, I am forced to describe their appearance.
Chapter 15, line 2夫唯不盈，故能蔽不新成。
Precisely because he does not crave fulfillment, can he preserve himself and avoid the lure of new accomplishment.
Chapter 15, line 12故令有所属，
therefore let people have something to hold on to:
Chapter 19, line 5不自见故明，不自是故彰，
Does not show himself, and therefore is apparent. Does not affirm himself, and therefore is acknowledged.
Chapter 22, line 5不自伐故有功，不自矜故长。
Does not boast and therefore has merit. Does not glorify himself and can therefore improve.
Chapter 22, line 6夫唯不争，故天下莫能与之争。
He does not contend, therefore the world cannot contend with him.
Chapter 22, line 7故飘风不终朝，
Similarly the wind does not blow the whole morning,
Chapter 23, line 2故从事于道者，
Thus, by engaging with the Way,
Chapter 23, line 7故有道者不处。
Thus, the daoist does not act like this.
Chapter 24, line 6故道大，天大，
Hence, the Way is great, the universe is great,
Chapter 25, line 8故无弃人；
and doesn't ostracize others.
Chapter 27, line 7常善救物，故无弃物，
He always takes care of things, and doesn't cast away anything.
Chapter 27, line 8故善人者，不善人之师；
Hence, the benefactor is the teacher of the lesser person,
Chapter 27, line 10故大制不割。
Therefore, great governance does not seek to process simplicity.
Chapter 28, line 12故物或行或随，
Thus, some things move, while some follow.
Chapter 29, line 5物或恶之，故有道者不处。
All things may loathe them, so the daoist does not keep them.
Chapter 31, line 2故能成其大。
it can achieve its greatness.
Chapter 34, line 9故失道而后德，失德而后仁，
So when the Way is lost, there is virtue; when virtue is lost, there is humaneness;
Chapter 38, line 9故去彼取此。
Thus he lets go of that, and takes up this.
Chapter 38, line 16故贵以贱为本，高以下为基。
So the noble has the humble as its root, and the high has the low as its base.
Chapter 39, line 12故致数舆无舆。
So if you count the parts of a carriage, there is no carriage.
Chapter 39, line 15故建言有之：
So the established sayings have it:
Chapter 41, line 7故物或损之而益，
So things may gain by being diminished,
Chapter 42, line 8是故甚爱必大费，
So great attachment is sure to cost much,
Chapter 44, line 4故知足之足，常足矣。
So the contentment of knowing what is enough is lasting contentment.
Chapter 46, line 5故道生之，德畜之。
So the Way gives them life and virtue nourishes them.
Chapter 51, line 5故以身观身，以家观家，
So observe the self through the self, the family through the family,
Chapter 54, line 9故不可得而亲，
So one cannot draw near to it,
Chapter 56, line 5故为天下贵。
So it is the most valued in the world.
Chapter 56, line 9故圣人云：
So the sage says:
Chapter 57, line 10夫两不相伤，故德交归焉。
Since neither harms the other, their virtue flows back to the people.
Chapter 60, line 5故大国以下小国，
So when a great state places itself below a small state,
Chapter 61, line 5故或下以取，
So one wins by lowering itself,
Chapter 61, line 8故立天子，置三公，
So when the Son of Heaven is enthroned and the three ministers appointed,
Chapter 62, line 5故为天下贵。
So it is the most valued in the world.
Chapter 62, line 10故能成其大。
and so he can achieve greatness.
Chapter 63, line 8故终无难矣。
and so in the end has no difficulty.
Chapter 63, line 12是以圣人无为故无败，
So the sage does not act, and so does not spoil;
Chapter 64, line 11无执故无失。
does not grasp, and so does not lose.
Chapter 64, line 12故以智治国，国之贼，
So to govern a state with cleverness is to rob the state;
Chapter 65, line 4故能为百谷之王。
so they can be kings of the hundred valleys.
Chapter 66, line 3以其不争，故天下莫能与之争。
Because he does not contend, no one in the world can contend with him.
Chapter 66, line 9夫唯大，故似不肖。
It is because it is great that it seems like nothing.
Chapter 67, line 3慈故能勇，
With compassion, one can be brave;
Chapter 67, line 8俭故能广，
with frugality, one can be generous;
Chapter 67, line 9故能成器长。
one can become the leader of all.
Chapter 67, line 11故抗兵相加，哀者胜矣。
So when armies meet, the side that grieves will win.
Chapter 69, line 7故去彼取此。
Thus he lets go of that, and takes up this.
Chapter 72, line 6故坚强者死之徒，
So the hard and stiff are companions of death;
Chapter 76, line 4
故 as “the reason”
Pattern 其 + 故
A noun, “cause, reason”, used once: 天之所恶，孰知其故 (chapter 73), “What heaven loathes, who knows why?”, word for word “who knows its reason?” Here 故 is the object of 知 “know”, after 其 “its”.
Once, in one line.
天之所恶，孰知其故？
What heaven loathes, who knows why?
Chapter 73, line 4
How to tell them apart
Position decides. At the head of a clause, followed by a statement, 故 is “therefore”; after 其 “its” or 何 “what”, it is a noun, “reason”. Compare 故能长生 (chapter 7), “Thus they can live long”, with 孰知其故 (chapter 73), “who knows why?”
The question 夫何故 (chapter 50), “Why is this?”, has the noun too; the word card treats 何故 as one word, “why”. 是故 (chapter 44), literally “this reason”, means the same: “for this reason, so”.