What we talk about when we talk about content externalism

Abstract

Some content externalists claim that if C is a theoretical concept and "C" expresses C, then the content of C in a community at a time is determined by how some members of the community at the time-call them "experts"-understand C or use "C". Thus, when non-expert Chauncey utters "C", the content of the concept he expresses does not depend entirely on his intrinsic physical properties, contra the claims of content internalism. This paper proposes that "concept" expresses a theoretical concept, such that the externalist's insights should apply to how we understand claims expressing the view itself and to how we evaluate the arguments alleged to motivate it. With respect to the first, I argue that the content externalist (a) should regard it as unclear at present which proposition her theory expresses, and (b) should take it that content externalism teaches us about our linguistic community rather than about the metaphysical nature of concepts. With respect to the second, I argue that by externalism's own lights, the famous externalist thought experiments shouldn't establish content externalism. In conclusion, I suggest that making sense of content externalism requires presupposing internalism.

Modelling the nucleon structure

“…This would suggest that the Jaffe-Manohar OAM is less than the Ji OAM. Preliminary lattice QCD calculations are consistent with this simple picture [29].…”

“…It is convenient to represent the correlator (29) in the four-component basis by the tensor Φ µν [32]. This tensor is related to helicity amplitudes as follows…”

“…(b) The basic idea of spectator models is to evaluate the TMD correlator (29) by inserting a complete set of intermediate states and then truncating this set at tree level to a single on-shell spectator diquark state, i.e. a state with the quantum numbers of two quarks.…”

“…The model relations ( 34)- (37) are not expected to hold identically in QCD. They can not be obtained at the level of the operators entering the definition of the TMDs in the correlator (29), but follow after the calculation of the matrix elements in (29) within a certain model for the nucleon state. Furthermore, the TMDs in these relations follow different evolution patterns: even if the relations are satisfied at some (low) scale, they would not hold anymore for other (higher) scales.…”

“…As far as the T-odd TMDs is concerned, their unique feature is the final/initial state interaction effects, which emerge from the gauge-link structure of the parton correlation functions (29). Without these effects, the T-odd parton distributions would vanish.…”