Control, Obviation, and Subjunctive Disjoint Reference

complex/control-pro showed you the control infinitive: a verb like vilja "want" or vona "hope" takes an að-infinitive whose silent subject (PRO) is locked to the matrix subject — ég vil fara "I want to go," where the goer is necessarily me. This page asks the question that lurks just beyond control: what happens when the goer is someone else? You cannot keep the control infinitive and somehow point it at a different person — the infinitive's subject is PRO, and PRO is bound to the matrix subject. Icelandic's answer is structural and decisive: it switches to a finite subjunctive clause, and that clause's subject is required to be disjoint from the matrix subject. So the same matrix verb governs two different complements depending on coreference — an infinitive when subjects match, a finite subjunctive when they differ. This is obviation, and the infinitive-vs-subjunctive contrast becomes a grammatical marker of who is doing the lower action. (For the mood itself, see complex/subjunctive-deep and verbs/subjunctive-wishes; this page is about the coreference it encodes.)

The basic split: same subject → infinitive, different subject → finite subjunctive

Start with vilja "want," the cleanest case. When the person who wants and the person who acts are the same, Icelandic uses the bare control infinitive — no að, no overt lower subject, just vil + infinitive. When they are different, the infinitive is impossible; you use a finite að-clause in the subjunctive, with the new subject spelled out.

Notice what English does and what Icelandic refuses to do. English uses an infinitive in both cases — "I want to go" and "I want him to go" — simply inserting an accusative subject ("him") before the infinitive in the second. Icelandic has no such accusative-subject infinitive after vilja: you cannot say \ég vil hann fara. The moment the subject changes, the whole complement changes shape — from an infinitive to a finite subjunctive clause introduced by *að. The structure itself carries the coreference information.

Obviation: the finite subjunctive's subject must be disjoint

Now the deeper fact, the one that makes this obviation rather than mere "use a clause for a different subject." The subject of the finite subjunctive complement is not merely allowed to differ from the matrix subject — under verbs like vilja, it is required to differ. You cannot use the finite subjunctive with a coreferent subject. \Ég vil að ég fari "I want that I go" is ungrammatical (or at best forces a bizarre split-self reading) — when the subjects corefer, the language *mandates the infinitive. So the two structures are in complementary distribution by coreference:

• coreferent subject → must use the infinitive (ég vil fara), cannot use the finite clause;
• disjoint subject → must use the finite subjunctive (ég vil að hann fari), cannot use the infinitive.

This is exactly the obviation familiar from Romance — French je veux qu'il parte (different subject, subjunctive) vs je veux partir (same subject, infinitive), with *je veux que je parte barred. Icelandic shows the same pattern, and competitor resources almost never name it as obviation: they teach the infinitive and the subjunctive clause as two separate constructions you happen to choose between, missing that the choice is governed by coreference and that the coreferent finite clause is forbidden. The slogan: under vilja, the complement type tells you whether the lower subject is the same as the matrix subject or different.

vona / vonast til: the same logic, with a wrinkle

vona "hope" (and the deponent vonast til (þess) að "hope to") behaves on the same axis, and it gives the cleanest minimal pair because the same verb appears with both an infinitive and a finite subjunctive. Same subject → infinitive; different subject → finite subjunctive. With vona/vonast, the finite subjunctive is used even for a coreferent subject in some registers (it is less strictly obviative than vilja), but the unmarked coreferent option is the infinitive, and a disjoint subject requires the finite clause.

The first two are a genuine minimal contrast worth pausing on: Ég vonast til að komast (infinitive, PRO = me) versus Ég vona að ég komist (finite subjunctive, overt ég) — both mean "I hope I make it," but the infinitive packs the coreference into PRO while the finite clause spells the coreferent subject out. The honest description is that vona tolerates the coreferent finite clause where vilja bars it, so the obviation effect is strict with vilja, softer with vona. That variation is real and you should not flatten it: the safe, idiomatic same-subject form is the infinitive in both, and the finite clause is required only when the subject is disjoint.

Why the subjunctive, and not the indicative?

A natural question: once you are forced into a finite clause for a disjoint subject, why is the verb subjunctive (fari, komist, kæmu) rather than indicative (fer, kemst, komu)? Because the matrix verbs here — vilja, vona, óska, verbs of wanting and hoping — describe a state of affairs the speaker wants to become true, not one asserted as fact. As complex/subjunctive-deep develops, the subjunctive is the mood of non-assertion: the wished-for going, coming, passing is desired, not vouched for as real. So the disjoint-subject complement is doubly marked — finite (because the subject is overt and disjoint) and subjunctive (because the matrix verb is desiderative). An indicative there would wrongly assert the lower event as fact.

Honest boundaries: overlap with control, raising, and binding

This phenomenon does not live in a sealed box, and pretending otherwise would mislead you. Three boundaries are worth marking explicitly.

First, the same-subject side is just control — the territory of complex/control-pro. Ég vil fara is a subject-control infinitive with PRO; nothing new about it except that it is now framed as one half of an obviation contrast. This page's contribution is the disjoint half and the complementarity between them.

Second, not every matrix verb is obviative. Obviation is a property of desiderative/volitional verbs (vilja, vona, óska); a verb like segja "say" or halda "think" takes a finite complement whose subject can perfectly well corefer with the matrix subject (hann segir að hann sé veikur "he says (that) he is sick" — hann can be the same person). So you cannot read "finite subjunctive ⇒ disjoint subject" as a global rule; it is specifically the volitional verbs that enforce obviation. Be careful which class your matrix verb is in.

Third, binding interacts but is separate. When a coreferent reading is available in a finite clause (as with segja), Icelandic often signals the intended coreference with the reflexive possessive or the long-distance reflexive sig/sér rather than the plain pronoun — a binding matter handled on its own page. The point to keep clean: obviation is about which complement type is licensed by coreference; binding is about which pronoun form marks coreference once a clause is there. They cooperate but answer different questions.

Common Mistakes

The flagship error for English speakers: calquing "I want that I go." Coreferent subjects under vilja force the infinitive; the finite clause is barred.

A direct calque of English "want him to go." Icelandic has no vilja + accusative + infinitive; a disjoint subject demands the finite subjunctive clause.

Even with the disjoint subject correctly in a finite clause, the verb must be subjunctive, because the matrix verb expresses a wish, not a fact.

Past matrix → past subjunctive in the complement; the indicative is wrong on both counts (mood and backshift).

The infinitive complement is reserved for the coreferent (same-subject) reading; a disjoint subject must go into a finite subjunctive clause.

Key Takeaways

• Icelandic encodes subject coreference in the choice of complement: same subject → control infinitive (Ég vil fara), different subject → finite subjunctive (Ég vil að hann fari). English uses an infinitive for both; Icelandic has no vilja
  • accusative + infinitive.
• This is obviation: under volitional verbs like vilja, the finite subjunctive complement requires a subject disjoint from the matrix subject, and the coreferent finite clause is barred (\Ég vil að ég fari) — a Romance-style pattern (cf. French *vouloir que).
• The two structures are in complementary distribution by coreference, so the complement type tells you whether the lower subject matches the matrix subject.
• The complement is subjunctive because the matrix verb is desiderative (non-assertive): Ég vil að þú farir, never indicative *ferð. A past matrix backshifts to the past subjunctive (vildi … kæmu).
• Boundaries: the same-subject half is ordinary control; obviation holds for volitional verbs (vilja, vona, óska) but not for verbs like segja/halda, whose finite complements allow coreference; and binding (which pronoun marks coreference) is a separate, cooperating system. vona enforces obviation more softly than vilja.