April 14th
15:00 to 18:00 (Buenos Aires local time)
SADAF (Bulnes 462)
SEAKER
SPEAKERS
Erik Stei (University of Utrecht)
Diego Tajer (University of Padua)
PROGRAMME
15-16: Erik Stei: The metalogic objection(s) to logical pluralism
16-17: Diego Tajer: A new metalogical argument for logical monism
ABSTRACTS
Erik Stei: The metalogic objection(s) to logical pluralism
Logical pluralism is a family of views united by the claim that there is more than one correct (or true, or legitimate) logic. Pluralist positions have received a fair bit of attention in the philosophy of logic, both sympathetic and critical. A more recent criticism of logical pluralism that has not been discussed in much detail, yet, is the so-called “metalogic objection” (Russell and Blake-Turner 2023) brought forward by Sereni and Sforza Fogliani (2020) and Griffiths and Paseau (2022).
In a nutshell, the challenge raised by those authors is this: “[l]ogical pluralists will [...] want to assert some metalogical sentences. They may want to weigh up the virtues of different logics, they may want to discuss the properties of different logics, and they may want to offer arguments to convince the other logicians to be pluralists. All of these are examples of metalogical claims” (Griffiths and Paseau 2022, 45). So, the question that needs to be answered is how many logics the logical pluralist is using when arguing for her position (Sereni and Sforza Fogliani 2020, 348) or when engaged in metalogical reasoning, more generally.
In the talk, I defend two theses. The first is that the metalogic objection is really based on two distinct questions: (i) which logic(s) may pluralists use when engaged in metalogical reasoning? and (ii) which logic(s) do pluralists rely on when justifying logical pluralism? The second thesis is that, to the extent that the metalogic objection raises any novel problems at all, these do not address logical pluralism exclusively–monists need to respond to them as well.
Diego Tajer: A new meta-logical argument for logical monism
Some authors have challenged logical pluralism under the so-called “metalogic objection”. The objection says that, even if one supports a plurality of logics, it is still unclear which logic one should use for proposing and justifying the pluralistic view (the intersection of all correct logics? one arbitrary correct logic?). One problem is that some of the correct logics may be too weak for meta-theoretical reasoning. Griffiths and Paseau (2022) argue that there is no reasonable response to the objection. For example, one cannot use one logic for the metalanguage and a different logic for the object language: a new “collapse” argument will emerge, and the meta-logic will trump any other logic. For this reason, they think that monism is unavoidable.
In this talk, I will claim that the argument by Griffiths and Paseau does not work. In principle, it is possible to use a strong logic for the metalanguage, and a weak logic to explain a specific phenomenon (such as vagueness or self-reference). However, I will argue that the meta-logical argument is correct, under a different formulation. If we accept a framework where one logic is used to build models and systems to understand many different phenomena, this meta-logic will be privileged (for it is general in a sense in which other logics are not), and therefore this pluralism will be more adequately characterized as a monism.