Antoni Antoszek
Jagiellonian University
The Thin Red Line semantics is one of the two main approaches to solving
the problem of future contingents in an indeterministic manner. The theory
claims that there is an actual future, but it is not determined. Despite the
development of the TRL semantics in recent years, the theory seems to fail to
represent any intuitive account of prediction-making. As the TRL function
assumes a “God’s eye” perspective and is not meant to serve any epistemic
goals, it appears that there is no way to accommodate everyday reasonings
into the TRL semantics.
In my paper, I argue that this does not have to be the case. I show
that there exists a function next, such that branching-time (BT) structures
M = ⟨M, <, TRL⟩ and N = ⟨M, <, next⟩ are definitionally equivalent.
My proof applies to discrete-time structures with usual BT axioms and T RL
defined for every counterfactual moment. I axiomatize the function next
by a single postulate: next^(k)(m1) = m2 ⇒ back^(k)(m2) = m1, where < turns out
to be enough to define back. Finally, I argue that next is closer to representing
everyday expectations and predictions than TRL: when one flips a coin, she
predicts that it will actually land either heads or tails (next function), and
does not predict every past and future state of affairs (TRL function).
Chair: Michael Stöger
Time: September 13th, 15:20-15:50
Location: SR 1.005
SOPhiA 2026 