Questions: Actualism and the Actuality Thesis

Question 1

Lewis says 'there could have been talking donkeys' is literally true because talking donkeys exist in a concrete possible world. An actualist agrees the statement is true. What does the actualist say makes it true?

• A. An abstract possible world — a maximal consistent set of propositions representing how things could be — without any concrete non-actual talking donkeys
• B. Nothing — actualists deny that modal statements like this can be true at all
• C. The indexical fact that, from our world, other concrete worlds appear to contain talking donkeys
• D. The causal history of actual donkeys, which shows they were genetically capable of evolving the capacity for speech

Answer: (A)

Actualists accept that modal statements can be true; they deny that their truth requires non-actual concrete entities. The standard actualist strategy appeals to abstract possibilia — possible worlds understood as abstract objects (maximal consistent propositions, states of affairs) rather than concrete universes. Option B mischaracterizes actualism as modal skepticism. Option C describes Lewis's own indexical view. Option D confuses metaphysical modality with causal or biological possibility.

Question 2

For David Lewis, the word 'actual' functions most like which ordinary term?

• A. A proper name that rigidly designates this particular world across all contexts
• B. An indexical like 'here' — meaning 'the world I am in,' so every world counts as actual relative to itself
• C. A description, picking out the world with the greatest number of existing beings
• D. A modal operator indicating that a proposition holds in all possible worlds

Answer: (B)

Lewis's view is that 'actual' is an indexical: just as 'here' picks out wherever the speaker is located, 'actual' picks out whatever world the speaker inhabits. From any world, that world is actual. This means there is no privileged, absolutely actual world — actuality is perspectival. The actualist rejects this and holds that actuality is absolute: there is a genuinely real actual world, and other 'worlds' are at most abstract constructions, not real alternatives.

Question 3

Actualism is more ontologically parsimonious than Lewisian modal realism because it does not posit an infinity of concrete non-actual universes.

• T. True
• F. False

Answer: True

True — this is one of actualism's main theoretical advantages. Lewis's modal realism requires accepting that an enormous plurality of concrete, spatiotemporally isolated universes exist as fully real as our own. Actualism avoids this commitment, analyzing modality through abstract constructions rather than concrete worlds. The theoretical cost of actualism is that it must explain what those abstract constructions are and how they represent modal truths — a burden modal realism sidesteps by brute ontological proliferation.

Question 4

According to actualism, the statement 'there could have been talking donkeys' is false, because no talking donkeys actually exist.

• T. True
• F. False

Answer: False

False — actualists accept that modal statements like this can be true; they simply give a different account of what makes them true. The actualist says the statement's truth is grounded in abstract possible worlds (or essences, or haecceities) rather than in the concrete existence of non-actual talking donkeys. What actualism denies is not modal truth, but the ontological claim that non-actual entities have genuine being.

Question 5

What is the core theoretical challenge actualism faces that Lewisian modal realism avoids, and how do actualists typically respond to it?

Model answer: Actualism must explain what modal statements are *about* if there are no non-actual entities to serve as their truthmakers. Lewis has a simple answer: 'possibly P' is true because P holds in some concrete possible world. The actualist cannot point to a concrete entity. The standard responses invoke abstract possibilia (maximal consistent sets of propositions or states of affairs that represent how things could be) or individual essences and haecceities (abstract properties an entity would have had if it had existed).

The key tension is between ontological parsimony and theoretical elegance. Actualism is parsimonious but must do more philosophical work to explain modal truth. Modal realism is ontologically extravagant but delivers a simple, uniform semantics. Understanding this tradeoff — not just the positions — is what it means to genuinely grasp actualism.