Many philosophers strive for a thin ontology but are nevertheless unwilling to curtail ordinary and scientific talk that carries apparent commitment to the entities they reject. As Carnap put it, such a philosopher speaks with an uneasy conscience, ‘like a man who in his everyday life does with qualms many things which are not in accord with the high moral principles he professes on Sundays.’ To appear less hypocritical he may, of course, tell us openly what he is doing and invite us to join him. But then it is hard to see why he is not advocating the absurd position that we should assent to sentences of the form ‘There are Fs but I don't believe that there are Fs.’

This is a simple objection, and there is a simple answer to it. But the answer is not available to everyone. I will argue that defenders of a particular version of fictionalism are in trouble with Moore's paradox. The bad news for fictionalism in general is that this particular version is the one that best deals with the Quine-Putnam challenge.

A skeptic will from time to time make such claims as ‘We know (little or) nothing.’ Call this the skeptical use of the word ‘know.’ In apparent contradiction of the skeptic's claims, almost all of us firmly ascribe knowledge to ourselves and others. We use the word ‘know’ and its cognates frequently and fluently in largely untroubled communication with our fellows. We make judgments ascribing knowledge to ourselves and others. Furthermore, faced with the same situation and needing to make a judgment about whether to ascribe knowledge or not, we agree on the whole with each other's ascriptions (and withholdings and doubtful cases). For the sake of a term, and being careful to neglect any stray connotations it may carry, let us call this the cognitivist use of ‘know.’

The doctrine of physicalism casts a long shadow in contemporary philosophy, configuring all kinds of philosophical issues and projects. Unsurprisingly, its proponents argue that physicalism has all the obvious features necessary for a scientific hypothesis to be in what we will call ‘good standing,’ i.e. being worthy of serious scientific investigation. In fact, many claim much more, arguing that physicalism is a well-confirmed hypothesis and possibly amongst the best of our theories. But, as our second opening passage makes clear, a persistent worry has been that physicalism, or ‘materialism’ as van Fraassen terms it, is an edifice built on sand. For many philosophers question whether the ‘physical’ can be specified at all, or at least in a manner that will produce a physicalism that would be in good standing.

Anyone who has ever lived with roommates understands the Hobbesian state of nature implicitly. People sharing accommodations quickly discover that buying groceries, doing the dishes, sweeping the floor, and a thousand other household tasks, are all prisoner's dilemmas waiting to happen. For instance, if food is purchased communally, it gives everyone an incentive to overconsume (because the majority of the cost of anything anyone eats is borne by the others). Individuals also have an incentive to buy expensive items that the others are unlikely to want. As a result, everyone's food bill will be higher than it would be if everyone did their own shopping. Things are not much better when it comes to other aspects of household organization. Cleaning is a common sticking point. Once there are a certain number of people living in a house, cleanliness becomes a quasi-public good. If everyone ‘pitched in’ to clean up, then everyone would be happier. But there is a free-rider incentive—before cleaning, it's best to wait around a bit to see if someone else will do it. As a result, the dishes will stack up in the sink, the carpet will get grungy, and so on.

Among the more notorious of Cartesian doctrines is the bête machine doctrine — the view that brute animals lack not only reason, but any form of consciousness (having no mind or soul). Recent English commentaries have served to obscure, rather than to clarify, the historical Descartes's views. Standard interpretations have it that insofar as Descartes intends to establish the bête machine doctrine his arguments are palpably flawed. One camp of interpreters thus disputes that he even holds the doctrine. As I shall attempt to show, not only does Descartes affirm the doctrine, his supporting arguments are not palpably flawed — even if they ultimately come up short. It will indeed emerge that, in making his case, Descartes employs interesting argumentative strategies that have not been duly appreciated.