Anthony E. Newman

Causal loops are circular chains of causally related events: each link causes others which in turn cause it. Not only are causal loops widely accepted as coherently conceivable; some are also provably self-consistent as well as seeming genuinely possible according to currently accepted laws of physics. On the common assumption that causation is transitive, each link in any causal loop would wind up causing itself; but the idea of self-causation is pretty much universally rejected as incoherent. A popular attempt to resolve this dilemma distinguishes “direct” from “indirect” self-causation: the direct variety, which operates without the aid of causal intermediaries, is claimed to be impossible even if the indirect variety isn’t. I argue against this attempted resolution on the grounds that causal loops themselves, unlike the links that compose them, should be viewed as directly self-caused; so indirect self-causation via causal loop is possible only if direct self-causation is as well. An important consequence is the availability of groundbreaking solutions to several longstanding puzzles in philosophy of mind.

Internalism about mental content holds that microphysical duplicates must be mental duplicates full-stop. Anyone particle-for-particle indiscernible from someone who believes that Aristotle was wise, for instance, must share that same belief. Externalism instead contends that many perfectly ordinary propositional attitudes can be had only in certain sorts of physical, sociolinguistic, or historical context. To have a belief about Aristotle, for instance, a person must have been causally impacted in the right way by Aristotle himself (e.g., by hearing about him, or reading some of his works).An interesting third view, which I call ‘weak’ internalism, is a mix of what are arguably the most plausible aspects of the two extreme views. On the one hand, the weak internalist rejects the externalist’s idea that certain propositional attitudes can be had only in certain sorts of physical, socio-linguistic, or historical context; but on the other hand, she rejects the internalist’s claim that microphysical duplicates must be mental duplicates. One of the most vocal opponents of externalism, John Searle, defends a paradigm case of weak internalism. In this paper I explain his view and why it might seem like the ideal compromise: in particular, it captures intuitions underlying both sides of the debate. I then argue, however, that Searle’s view is untenable; and my objection shows the untenability of weak internalism in general. Despite the attractiveness of a compromise view, we must choose between internalism and externalism full-stop.

Externalism says that many ordinary mental contents are constituted by relations to things outside the mental subject’s head. An influential objection says that externalism is incompatible with our commonsense belief in mental causation, because such extrinsic relations cannot play the important causal role in producing behavior that we ordinarily think mental content plays. An extremely common response is that it is simply obvious, from examples of ordinary causal processes, that extrinsic relations can play the desired causal role. In this paper I argue that such examples show no such thing, and that the only reason to think they do is to endorse an unacceptable principle concerning the sufficient conditions for causal efficacy. Internalists might be wrong that externalism is incompatible with mental causation; but the most common defense against that allegation should not move us at all.

Recent philosophy of psychology has seen the rise of so-called "dual-component" and "two-dimensional" theories of mental content as what I call a "Middle Way" between internalism (the view that contents of states like belief are "narrow") and externalism (the view that by and large, such contents are "wide"). On these Middle Way views, mental states are supposed to have two kinds of content: the "folk-psychological" kind, which we ordinarily talk about and which is wide; and some non-folk-psychological kind which is narrow. Jerry Fodor is responsible for one of the most influential arguments that we need to believe in some such non-folk-psychological kind of content. In this paper I argue that the ideas behind Fodor's premises are mutually inconsistent - so it would be irrational to believe in a Middle Way theory of mental content no matter how many of Fodor's premises you find plausible. Common opinion notwithstanding, we have to choose between internalism and externalism, full-stop

Internalism about mental content is the view that microphysical duplicates must be mental duplicates as well. This dissertation develops and defends the idea that only a strong version of internalism is compatible with our commonsense commitment to mental causation. Chapter one defends a novel necessary condition on a property's being causally efficacious---viz., that any property F that is efficacious with respect to event E cannot be instantiated in virtue of any property G that is itself ceteris paribus sufficient for E---and shows that that necessary condition vindicates the idea that externalism is incompatible with our commonsense commitment to mental causation. The internalist's core intuition is that only intrinsic properties can be causally efficacious. Chapter two defends that intuition from the common externalist response that extrinsic properties abound. A popular "Middle Way" between externalism and internalism holds that although ordinary, "folk-psychological" contents of prepositional attitudes are extrinsic, there exists some other non-folk-psychological kind of content that is intrinsic. Chapter three argues that Jerry Fodor's influential argument for the Middle Way is incoherent. Chapter four identifies a weak but popular grade of internalism, endorsed by John Searle among others, and argues that it is untenable. The preceding defense of internalism can be believed only if there is something wrong with the canonical arguments for externalism developed by Hillary Putnam, Tyler Burge, and Saul Kripke. My postscript says what I think is wrong with the canonical externalist arguments: they assume the nonexistence of propositions that are truth-evaluable only relative to particular persons, places, or times; while I argue that our commonsense commitment to mental causation requires at least some such "indexical propositions"