From two facts to one explicit relationship
These markers do more than connect sentences: they tell readers exactly how the second claim rests on the first. A writer may name an actual outcome, draw a conclusion from premises, extend an argument to a related case or offer only a probable explanation.
Identify the relationship between the claims before choosing the word. Therefore can present either a practical result or a step in reasoning; context, not the marker alone, establishes the precise meaning.
basis or cause → marker → consequence / inference with an appropriate degree of certainty
The access code expired. Consequently, the team could not enter the archive.
The access code expired. Consequently, the team could not enter the archive.
Consequently names an actual outcome: the expired code really caused the team's inability to enter.
Every valid claim has a reference number. This claim has none. Therefore, it is not valid.
Every valid claim has a reference number. This claim has none. Therefore, it is not valid.
Therefore presents an inference from two explicitly stated premises.
An event's consequence and the writer's inference are different
Consequently and as a result most transparently present the second situation as a result of the first. Therefore and thus are often broader: they can introduce either an outcome or a step in an argument. It follows that explicitly derives a conclusion from premises, while on that basis shows that the preceding facts provide grounds for a judgement or decision.
Do not confuse causation with logical support. A forecast may provide grounds for postponing a launch, but the forecast itself does not physically cause every subsequent event. In such a context, on that basis is often more precise than consequently.
actual cause → consequently / as a result; premises → therefore / it follows that / on that basis
The coolant pump stopped; as a result, the reactor shut down automatically.
The coolant pump stopped; as a result, the reactor shut down automatically.
The second event is an actual operational consequence of the first.
The forecast shows a persistent deficit. On that basis, the board has postponed the expansion.
The forecast shows a persistent deficit. On that basis, the board has postponed the expansion.
The forecast is the basis for the decision; the marker does not exaggerate it into a physical cause.
The two premises cannot both be true. It follows that at least one must be rejected.
The two premises cannot both be true. It follows that at least one must be rejected.
It follows that makes the deductive step explicit.
The strength of an inference: necessity, grounds or probability
It follows that and therefore can present a conclusion as logically supported. However, a marker cannot repair weak reasoning: correlation, a few complaints or indirect signs do not by themselves prove causation or a general rule.
Apparently means that a claim matches what has been heard, read or appears to be the case. Presumably presents what the speaker considers probably true. Both leave room for error. For finer calibration, add may, seems, suggests or does not necessarily follow.
strong premises → it follows that; incomplete signs → apparently / presumably / may; unwarranted necessity → does not necessarily follow
The lights are on, but nobody has answered. Presumably, someone is still working inside.
The lights are on, but nobody has answered. Presumably, someone is still working inside.
This is a plausible inference from indirect signs, not an established fact.
Sales and advertising rose together. It does not necessarily follow that advertising caused the entire increase.
Sales and advertising rose together. It does not necessarily follow that advertising caused the entire increase.
The expression explicitly limits an excessively strong causal inference.
Apparently, the permit was renewed, although we have not yet seen the document.
Apparently, the permit was renewed, although we have not yet seen the document.
Apparently marks information based on signs or a report while preserving uncertainty.
Profiles of formal markers
In formal style, thus can mean as a result or in this way. Hence means for this reason and often compresses a conclusion into a noun phrase: hence the delay. By extension applies an argument to a related case; it is not simply the next event in time.
A common explicit pattern is It follows that + a complete clause. That is sometimes omitted, but it helps mark the clause boundary in a complex formal argument. In It follows, then, that…, parenthetical then is set off by commas; it need not be added to every conclusion.
hence + noun phrase | it follows that + complete statement | by extension + related case
- NP / noun phrase —
- A noun phrase: a noun with its dependent words, such as the new student; the pattern treats it as one group of words.
- noun —
- A word naming a person, thing or idea: student, book, happiness.
The permit has expired, hence the need to submit a new application.
The permit has expired, hence the need to submit a new application.
Hence is followed by the noun phrase the need, not an all-purpose that-clause.
The rule protects employees with privileged access and, by extension, contractors with the same access.
The rule protects employees with privileged access and, by extension, contractors with the same access.
The rule's logic extends to a related group sharing the same relevant feature.
The method removes duplicate records, thus reducing the error rate.
The method removes duplicate records, thus reducing the error rate.
Thus reducing… means thereby reducing…. It is an -ing construction, not a separate independent sentence.
Position and punctuation depend on the construction
At the beginning of a separate sentence, a linking adverb is usually followed by a comma: Consequently, the test was repeated. Between two independent clauses in formal writing, a full stop or semicolon is appropriate: The test failed; therefore, we repeated it. A comma alone cannot do the semicolon's job.
After a coordinating conjunction such as and, the marker is often integrated without paired commas: The test failed and therefore had to be repeated. A parenthetical reading is punctuated differently: We will, therefore, repeat the test. Punctuation depends on the structure and the marker's role.
sentence. Therefore, next sentence. | independent clause; therefore, independent clause | subject + predicate and therefore second predicate
- subject / S —
- The grammatical subject: who or what the clause is about; the verb agrees with it. In The book was written, the book is the subject, although someone else does the action.
- clause —
- A construction with a verb, often with its own subject: when I arrived. A non-finite clause may leave the subject unspoken: to get home.
The audit is incomplete; therefore, publication must wait.
The audit is incomplete; therefore, publication must wait.
The semicolon separates two independent clauses, while the comma sets off the introductory marker in the second.
The audit is incomplete and therefore cannot support publication.
The audit is incomplete and therefore cannot support publication.
Therefore is integrated into the coordinated predicate after and; a universal pair of commas is not required.
We will, therefore, reopen the review.
We will, therefore, reopen the review.
In this position, therefore is parenthetical and set off on both sides.
Check the bridge between the grounds and the claim
Before using a strong marker, state the hidden premise: exactly why does the given fact support the conclusion? If the bridge is weak or alternative explanations exist, change not only the marker but also the strength of the claim. Presumably and apparently do not turn an unsupported claim into a sound argument, but they honestly signal uncertainty about what is true.
By extension also requires a shared relevant feature. You cannot extend a rule to a new group merely because it is mentioned nearby. On that basis must clearly refer to visible grounds; otherwise readers cannot tell what supports the decision.
Three sensors report the same fault. On that basis, we recommend an immediate manual inspection.
Three sensors report the same fault. On that basis, we recommend an immediate manual inspection.
The visible body of data supports a practical recommendation without presenting the diagnosis as a proven fact.
Two clients complained. This suggests a problem, but it does not follow that every client is dissatisfied.
Two clients complained. This suggests a problem, but it does not follow that every client is dissatisfied.
The sentence acknowledges evidence while blocking an unsupported generalisation.
A procedure for your own writing
Identify the first claim as a cause, evidence, a rule or merely a sign. Decide what you do next: describe an event, derive a necessary conclusion, make a decision, extend a rule or propose an explanation. Choose the marker by function, check the claim's strength, then punctuate the actual syntactic framework you have built.
When editing, remove the marker and describe the relationship in your own words. This happened because of the preceding event calls for a result marker; I infer this from these premises calls for an inference marker; this only appears to be true calls for an expression of uncertainty.
The threshold was exceeded. Consequently, the alarm activated. The readings may, however, reflect a faulty sensor; it does not follow that the building is unsafe.
The threshold was exceeded. Consequently, the alarm activated. The readings may, however, reflect a faulty sensor; it does not follow that the building is unsafe.
The paragraph separates an actual technical outcome from a cautious interpretation of the evidence.
Under this policy, every processor and subprocessor must encrypt personal data. The vendor is a processor. It follows that the vendor must encrypt personal data; the same requirement applies to its subprocessors.
Under this policy, every processor and subprocessor must encrypt personal data. The vendor is a processor. It follows that the vendor must encrypt personal data; the same requirement applies to its subprocessors.
Both groups are explicitly covered by the initial premise. The conclusion rests on it without adding a new obligation absent from that premise.
Common mistakes
Incorrect:The pilot failed, therefore, the release was halted.
Correct:The pilot failed; therefore, the release was halted.
Two independent clauses cannot be joined by a comma alone; therefore needs a semicolon or full stop before it here.
Incorrect:It follows, then, that demand will exceeds supply.
Correct:It follows, then, that demand will exceed supply.
Will requires the base form exceed without -s. It follows that introduces the conclusion, while then is parenthetical here.
Incorrect:By extend, the policy covers contractors.
Correct:By extension, the policy covers contractors.
The fixed formal marker contains the noun extension, not the verb extend.
Incorrect:The sample was contaminated. Consequently of this, the result is unusable.
Correct:The sample was contaminated. Consequently, the result is unusable.
Consequently is an adverb and does not take of this; as a consequence of this is a separate construction.
Incorrect:The evidence is conclusive. It follow that the claim is false.
Correct:The evidence is conclusive. It follows that the claim is false.
In the impersonal frame, the subject it requires third-person singular follows.
Incorrect:The permit expired, hence that we must reapply.
Correct:The permit expired; hence, we must reapply.
Hence does not introduce a that-clause on the model of it follows that; here it is a linking adverb between two independent clauses.
Sources
- Oxford Advanced Learner’s Dictionary: therefore
- Oxford Advanced Learner’s Dictionary: consequently
- Oxford Advanced Learner’s Dictionary: thus
- Oxford Advanced Learner’s Dictionary: hence
- Oxford Advanced Learner’s Dictionary: presumably
- Oxford Advanced Learner’s Dictionary: apparently
- Oxford Advanced Learner’s Dictionary: follow
- Oxford Advanced Learner’s Dictionary: extension