Short answer. Substitution is the appointment of another heir who enters into the inheritance only in default of the heir originally instituted. Article 857 makes the substitute's right conditional — the substitute inherits when the original heir does not, for whatever reason leaves that heir out of the succession.
What the law says
Substitution is the appointment of another heir so that he may enter into the inheritance in default of the heir originally instituted.
Civil Code, Article 857 — Substitution Defined. Read the full provision →
A second name, for a specific situation
Article 857 defines substitution as the appointment of another heir so that he may enter into the inheritance in default of the heir originally instituted. A substitute is not a co-heir sharing the inheritance alongside the original heir from the start. The substitute is named to step in for a specific reason: because the heir originally instituted, for whatever cause, does not end up receiving the inheritance.
The condition is 'in default of' the first heir
The phrase in default of is the key to when a substitute actually inherits. The substitute's right does not exist independently of the original heir's position — it depends on that heir being absent from the succession in some way the testator anticipated when naming a substitute. Until that default happens, the substitute has been named but has not yet entered into anything; the inheritance belongs, in the first instance, to the heir originally instituted. Article 859 spells out the cases the testator may have in mind: the substitute may be designated to take over in case such heir or heirs should die before him, or should not wish, or should be incapacitated to accept the inheritance. It adds a default worth knowing: a simple substitution that does not say which case it refers to covers all three, unless the testator provided otherwise. A bare clause naming a substitute is therefore broad, not narrow.
Two heirs, two different relationships to the inheritance
Reading Article 857 carefully shows two distinct roles: the heir originally instituted, who is the primary object of the testator's disposition, and the substitute, who is appointed with reference to that first heir's possible absence. The substitute's entire claim under this article is built on the first heir's default — the substitution exists precisely to answer the question of what happens to the inheritance if the original heir does not take it. Article 858 lists four forms the arrangement can take — simple or common, brief or compendious, reciprocal, and fideicommissary — and they are not interchangeable. The fideicommissary kind in particular is a different animal: there the first heir is charged with preserving the property and transmitting it to a second heir, so both inherit in turn rather than one taking only if the other fails.
Why this distinction matters when reading a will
Someone reading a will that names both an heir and a substitute should not treat the two as equally entitled from the outset. Article 857 frames the substitute's entitlement as arising only in default of the original heir — so the first question is always whether that default has actually occurred. Only once it has does the appointment of the substitute under this article become relevant to who actually inherits. It is also worth checking which of the forms in Article 858 the clause actually creates, because a badly drafted substitution and a fideicommissary one can read alike on the page and lead to very different results.
Related provisions
- Civil Code, Article 857 — Substitution Defined
- Civil Code, Article 858 — The Four Kinds of Substitution
- Civil Code, Article 859 — Simple Substitution