Online research in philosophy

We provide partial answers to the following problem: Is the class of Borel linear orders well-quasi-ordered under embeddability? We show that it is indeed the case for those Borel orders which are embeddable in R ω , with the lexicographic ordering. For Borel orders embeddable in R 2 , our proof works in ZFC, but it uses projective determinacy for Borel orders embeddable in some $\mathbf{R}^n, n , and hyperprojective determinacy for the general case.

Carlo Rovelli's relational interpretation of quantum mechanics holds that a system's states or the values of its physical quantities as normally conceived only exist relative to a cut between a system and an observer or measuring instrument. Furthermore, on Rovelli's account, the appearance of determinate observations from pure quantum superpositions happens only relative to the interaction of the system and observer. Jeffrey Barrett ([1999]) has pointed out that certain relational interpretations suffer from what we might call the ‘determinacy problem', but Barrett misclassifies Rovelli's interpretation by lumping it in with Mermin's view, as Rovelli's view is quite different and has resources to escape the particular criticisms that Barrett makes of Mermin's view. Rovelli's interpretation still leaves us with a paradox having to do with the determinacy of measurement outcomes, which can be accepted only if we are willing to give up on certain elements of the ‘absolute’ view of the world.

We characterize, in terms of determinacy, the existence of the least inner model of "every object of type k has a sharp." For k ∈ ω, we define two classes of sets, (Π 0 k ) * and (Π 0 k ) * + , which lie strictly between $\bigcup_{\beta and Δ(ω 2 -Π 1 1 ). Let ♯ k be the (partial) sharp function on objects of type k. We show that the determinancy of (Π 0 k ) * follows from $L \lbrack\ sharp_k \rbrack \models "\text{every object of type} k \text{has a sharp},$ and we show that the existence of indiscernibles for L[ ♯ k ] is equivalent to a slightly stronger determinacy hypothesis, the determinacy of (Π 0 k ) * +.

We show that Blackwell determinacy in L(R) implies determinacy in L(R).

We characterize, in terms of determinacy, the existence of 0 ♯♯ as well as the existence of each of the following: 0 ♯♯♯ , 0 ♯♯♯♯ ,0 ♯♯♯♯♯ , .... For k ∈ ω, we define two classes of sets, (k * Σ 0 1 ) * and (k * Σ 0 1 ) * + , which lie strictly between $\bigcup_{\beta and Δ(ω 2 -Π 1 1 ). We also define 0 1♯ as 0 ♯ and in general, 0 (k + 1)♯ as (0 k♯) ♯ . We then show that the existence of 0 (k + 1)♯ is equivalent to the determinacy of ((k + 1) * Σ 0 1 ) * as well as the determinacy of (k * Σ 0 1 ) * +.

A number of important legal theorists have recently argued for metaphysically realist approaches to legal determinacy grounded in particular semantic theories or theories of reference, in particular, views of meaning and reference based on the works of Putnam and Kripke. The basic position of these theorists is that questions of legal interpretation and legal determinacy should be approached through semantic meaning. However, the role of authority (in the form of lawmaker choice) in law in general, and democratic systems in particular, require that these realist solutions to the problem of legal determinacy be rejected, or at least significantly revised.