In a possible world where you were born in a different country, have different beliefs, and speak a different language, what does the haecceitist claim makes the person in that world you rather than a qualitatively similar but numerically distinct individual?
AThat person shares all your actual qualitative properties — the scenario is internally inconsistent
BThat person instantiates your haecceity — the non-qualitative property of being-you — which is preserved across all possible worlds in which you exist
CThat person is connected to you through a continuous spatio-temporal chain stretching back to your birth
DThat person is you because the description 'born in a different country' refers back to the actual you via Kripkean rigid designation
The haecceitist answers that transworld identity is grounded in a non-qualitative individual essence — a haecceity — that a person carries necessarily across all possible worlds in which they exist. Even in worlds with dramatically different qualitative profiles, the individual is numerically identical to the actual person because they instantiate the same primitive thisness. This is why haecceities are invoked: qualitative properties alone cannot settle which possible person 'is' you, because any number of qualitatively distinct individuals could be stipulated. The haecceity provides an additional metaphysical peg beyond the qualitative.
Question 2 Multiple Choice
A philosopher objects: 'Haecceities are defined as non-qualitative, which means they have no descriptive content I can perceive, measure, or use to identify individuals across worlds. So what theoretical work are they actually doing beyond labeling the problem?' This objection is best characterized as:
AA parsimony objection — haecceities multiply entities beyond necessity
BAn epistemic objection — haecceities are undetectable and have no descriptive content, so they cannot explain what they're meant to explain
CA semantic objection — the word 'haecceity' is grammatically malformed and has no meaning
DA causal objection — haecceities cannot enter into causal relations and therefore cannot affect anything
The epistemic objection targets the non-qualitative nature of haecceities specifically. If a haecceity is not a qualitative feature — it does not describe height, origin, history, beliefs, or any observable property — then it is epistemically inaccessible. We cannot detect, measure, or even describe haecceities, which raises the question of whether positing them explains anything at all, or merely re-labels the intuition we started with ('this individual is this individual'). The parsimony objection (option A) is also a real objection, but the quoted passage specifically targets the lack of descriptive content, which is the epistemic critique.
Question 3 True / False
According to haecceitism, two qualitatively identical individuals existing in different possible worlds could still be numerically distinct persons, each possessing their own unique haecceity.
TTrue
FFalse
Answer: True
True, and this is one of the core commitments of haecceitism. The principle of identity of indiscernibles (Leibniz's law) says that if two things share all their properties, they are identical. But haecceitism denies that qualitative identity entails numerical identity: two individuals can be qualitatively indistinguishable and yet be two distinct individuals, because each has their own primitive thisness — their own haecceity — that distinguishes them. This is sometimes called the possibility of 'symmetric worlds': a world with two qualitatively identical globes that are nonetheless numerically distinct. Anti-haecceitists (like many bundle theorists) deny this scenario is coherent.
Question 4 True / False
Haecceities are qualitative properties that distinguish one individual from another by describing unique features such as birth location, genetic profile, or personal history.
TTrue
FFalse
Answer: False
False. This gets the concept exactly backwards. A haecceity is explicitly non-qualitative — it is precisely what distinguishes an individual beyond any qualitative features. Qualitative properties (height, history, beliefs, genetics) can in principle be shared by distinct individuals, or can vary across possible worlds while the individual persists. The haecceity — 'being-this-individual' — is the additional metaphysical element that explains individuation after all qualitative facts are fixed. If haecceities were just sets of unique qualitative properties, they would add nothing to accounts that already individuate via qualitative bundles.
Question 5 Short Answer
Why does transworld identity create a problem that qualitative properties alone cannot solve? What gap does the concept of haecceity fill?
Think about your answer, then reveal below.
Model answer: When we say 'you could have been born elsewhere' or 'that war might not have happened,' we seem to be making claims about specific individuals existing in other possible worlds with different qualitative profiles. But if identity across worlds is fixed purely by qualitative properties, then the individual with your actual qualitative bundle just IS you, making it impossible to coherently describe a counterpart with different qualities as being you. Haecceity fills this gap by providing a non-qualitative identity-constituting property — a primitive thisness — that an individual carries across worlds regardless of qualitative variation. Without it, modal claims about specific individuals lose their ground.
The problem can be felt directly: consider the scenario where you and your best friend swap birth positions. Intuitively, this seems possible — you could have been born elsewhere. But if the person born at your actual birthplace with your actual genetic endowment IS you by definition, the swap scenario is incoherent: the person born elsewhere would just be a qualitatively different individual, not you. Haecceitism preserves the intuition that you are the same individual across qualitative variation by adding a non-qualitative anchor. Critics argue Kripkean causal theories of names accomplish the same thing more economically.