Understanding When to Use “That Which” in English Grammar
“That which” often stumps even fluent writers. The phrase carries subtle rules rooted in grammatical roles, register, and rhythm.
Mastering it sharpens clarity, elevates tone, and prevents the awkward omissions that can jar readers.
The Core Grammatical Function
Relative Clauses and Antecedents
A relative clause modifies a noun, and “that which” acts as a fused relative pronoun, combining the antecedent and the relative word in one unit.
Example: “She kept that which mattered” fuses the object (“that”) and the relative pronoun (“which”) into a single grammatical package.
Subject vs. Object Positioning
When the fused phrase serves as the grammatical subject, the verb agrees with the singular “that.”
Example: “That which inspires us drives innovation.” The verb “drives” agrees with the singular subject “that.”
Prepositional Complements
“That which” can also follow prepositions, forming compact adverbial phrases.
Example: “From that which we learn, we build new theories.” The preposition “from” governs the entire fused phrase.
Register and Tone Considerations
Formal Academic Writing
Academic prose favors “that which” when referencing abstract concepts already under discussion.
Example: “The study isolates that which distinguishes neural networks from symbolic systems.” The phrase signals precision and avoids vague pronouns.
Conversational Alternatives
In casual speech, “what” or “the thing that” replaces “that which” to keep dialogue light.
Example: Instead of “Keep that which you need,” say “Keep what you need.” The substitution shortens the utterance and aligns with spoken rhythm.
Literary Styling
Poets exploit the archaic resonance of “that which” to evoke weight and timelessness.
Example: “He sought that which no map could chart.” The phrase stretches the sentence, matching the epic tone.
Semantic Precision in Abstract References
Distancing from Concrete Nouns
Use “that which” when the referent is an entire idea, process, or condition rather than a countable object.
Example: “Respect that which cannot be quantified.” The phrase points to the abstract notion of value itself, not a specific item.
Highlighting Contrastive Sets
Deploy the phrase to emphasize a boundary between inclusion and exclusion.
Example: “Reward that which aligns with policy, not that which merely appears innovative.” The dual repetition sets up a clear contrast.
Avoiding Ambiguous Pronouns
When multiple nouns precede the clause, “that which” clarifies which concept is being modified.
Example: “The theory and its proof—keep that which withstands scrutiny.” The fused phrase locks the reference to the proof alone.
Placement in Complex Sentences
Mid-Sentence Insertions
Insert the phrase after a linking verb to add explanatory detail without a new clause.
Example: “The goal is that which unites the team.” The complement elaborates on “goal” in a single breath.
Initial Position for Emphasis
Starting a sentence with “That which” places thematic focus on the abstract quality under discussion.
Example: “That which fuels curiosity cannot be legislated.” The fronted structure grants the clause rhetorical weight.
Embedded Subordinate Clauses
Within a larger relative clause, the phrase can act as an object of the subordinate verb.
Example: “The data reveal patterns in that which investors overlook.” The embedded clause nests neatly without comma disruption.
Punctuation and Flow Mechanics
Comma Restrictions
Because “that which” introduces restrictive information, omit commas.
Example: “Accept that which serves the mission.” The absence of commas signals necessity.
Semicolon Bridges
Use a semicolon before “that which” when linking two balanced clauses.
Example: “The algorithm evolves; that which stagnates is discarded.” The semicolon tightens the logical link.
Colon Expansion
A colon can precede the phrase when the first clause sets up an explanation.
Example: “Innovation demands one thing: that which challenges orthodoxy.” The colon amplifies the definition.
Comparison with Similar Constructions
“That which” vs. “What”
“What” is the fused form common in speech and informal writing.
Example: “Keep what matters” is shorter but less formal than “Keep that which matters.”
“That which” vs. “Those which”
Use “those which” only when the antecedent is plural and countable.
Example: “Select those which passed inspection” contrasts with “Select that which passed inspection” for a singular concept.
“That which” vs. “The thing that”
“The thing that” adds explicitness but can feel wordy.
Example: “Respect the thing that drives you” is clearer yet heavier than “Respect that which drives you.”
Common Pitfalls and Quick Fixes
Redundant Second “That”
Writers sometimes insert an extra “that” after “that which,” creating clutter.
Incorrect: “Accept that which that supports your goal.” Remove the second “that” immediately.
Misplaced Verb Agreement
When the phrase heads a clause, the verb must stay singular even if the complement is plural.
Example: “That which bring results is valued” should read “That which brings results is valued.”
Overusing in Technical Lists
In bullet points or tables, the phrase can bloat concise items.
Fix: Replace “Retain that which meets spec” with “Retain items meeting spec.”
Advanced Stylistic Variations
Inverted Order for Dramatic Effect
Flip the clause to place the verb first, then “that which.”
Example: “Rare is that which defies entropy.” The inversion sharpens poetic punch.
Elliptical Reductions
In headlines, drop the verb following “that which” if context supplies it.
Example: “Cherish that which endures.” The ellipsis keeps the line crisp yet understood.
Layered Modification
Stack adjectives before “that which” to compress multiple qualifiers.
Example: “Embrace only tested, peer-reviewed, reproducible that which advances science.” The front-loaded modifiers create urgency.
Cross-Linguistic Insight
Germanic Parallels
German “das, was” mirrors “that which,” reinforcing the fused relative concept.
Example: “Das, was zählt, bleibt” translates directly to “That which counts remains.”
Romance Language Equivalents
French “ce qui” and Spanish “lo que” serve similar functions but allow looser placement.
Observing these parallels helps bilingual writers avoid calque errors.
Japanese Zero-Pronoun Contrast
Japanese often omits the relative pronoun entirely, a pattern that can mislead learners into dropping “which” in English.
Reminder: English retains the pronoun to mark the clause boundary.
Editing Workflow Checklist
First-Pass Scan
Search your draft for every instance of “that which” and question necessity.
If the noun is concrete or countable, switch to “the one that” or simply “which.”
Register Alignment
Match each use to the intended audience; academic journals welcome the phrase, social media posts rarely do.
Adjust tone by substituting “what” or rephrasing entirely.
Read-Aloud Test
Speak the sentence to detect rhythmic drag.
If the phrase stumbles, compress or split the clause for better cadence.
Micro-Edits for Clarity
Replace with Noun Phrase
Swap “that which” for a precise noun when the referent is named earlier.
Example: Instead of “Review that which we discussed,” write “Review the protocol we discussed.”
Shift to Active Voice
Move the agent to the front to reduce word count.
Example: “We retain that which works” becomes “We retain what works.”
Combine with Participial Clause
Merge the relative clause into a participial phrase to tighten flow.
Example: “That which was discovered yesterday” simplifies to “Discovered yesterday.”
Contextual Mini-Case Studies
Legal Brief Excerpt
Original: “The plaintiff seeks that which was promised.”
Revision: “The plaintiff seeks the promised relief.” The noun phrase clarifies the demand.
Marketing Copy Sample
Original: “Unlock that which drives growth.”
Revision: “Unlock the driver of growth.” The change keeps the hook but shortens the line.
Scientific Abstract Fragment
Original: “We isolate that which modulates synaptic plasticity.”
Accepted: “We isolate the factor modulating synaptic plasticity.” The edit meets journal brevity standards.
Historical Evolution Snapshot
Early Modern English Usage
Shakespearean texts show heavy reliance on “that which” for rhetorical grandeur.
Example: “Lord, we know what we are, but know not what we may be” originally framed as “that which we may be.”
19th Century Compression
Victorian editors trimmed the phrase to “what” in reprints to suit mass-market readability.
This shift marks the beginning of the modern preference for brevity.
Digital Age Trends
SEO algorithms favor concise keywords, pushing writers toward “what” in headings and metadata.
Yet formal white papers still retain “that which” to signal authority.
Practice Drills for Mastery
Sentence Transformation
Take five sentences using “that which” and rewrite each with “what,” “the thing that,” and a noun phrase.
Compare rhythm, tone, and clarity to internalize the trade-offs.
Paragraph Rewrite
Select a 150-word paragraph dense with fused relatives and compress it to 100 words without loss of meaning.
This forces strategic omission and synonym choice.
Voice Swap Exercise
Convert a formal paragraph into conversational prose, then back again.
Notice when “that which” survives the round trip and when it vanishes.
Diagnostic Troubleshooting
Flagging Overuse
If a single page contains more than three instances, highlight each and justify retention.
Odds are at least one can be cut or rephrased.
Checking Ambiguous Reference
Circle every “that which” and draw an arrow to its implied antecedent.
If the arrow crosses more than one potential noun, recast the sentence.
Listening for Redundancy
Record yourself reading the text; any stumble usually signals excess verbiage.
Prune until the sentence flows in a single breath.