Yes, many philosophers have conducted investigations into different concepts or themes other than those investigated by Foucault. Lad Sessions, for example, has done a good book on the concept of faith, outlining philosophically significant different notions of faith and, more recently, he has looked at the concept of honor (the book is called Honor For Us and is published by Continuum), Douglas Hedley has done some great work on the idea of the imagination, and the like. I am in the midst of being the co-editor with Chad Meister, The History of Evil with Acumen Press, a six volume work involving about 100 scholars who will look at "the history and changes of a concept," namely the concept of evil. Alas, it will probably not come out to 2014, but this might be something of interest.

You suggest that Kant's criterion of wrong conduct turns on this question: "If everyone acted the way I am proposing to act, would this have undesirable consequences?"

I think Kant's actual question differs in two respects. Kant is not asking whether the agent would like some fictional world (find it desirable), but whether the agent can will it and her own proposed conduct in it. And the world Kant envisioned is not one in which all act the way the agent is proposing to act, but one in which all are permitted (and take themselves to be permitted) so to act. So Kant's question is: "Can I will the action I am considering along with its universal permission?" The basic idea here is that I should not permit myself an action that I cannot permit all others at the same time.

Let's see how this plays out in Kant's promising example. The agent considers extricating himself from financial difficulty by making a false (lying) promise. He then asks himself whether, in a world in which all took themselves to be permitted to make such promises, he could still will to act in this way. Kant's answer is no: in that fictional world, such promises would not be believed and therefore refused; and agents could thus not will to offer them because they would be useless for their intended purpose.

Now your objection survives this clarification. Suppose the world were such that some nice fairy fulfilled any promises that the promisor fails to fulfill. In that world, it would seem, making false promises would be permissible. For in that world, even if all took themselves to be permitted to make false promises, such promises would (not be believed but) still be accepted. In that world, then, the agent can will his proposed action alongside its universal permission. So it would seem that, as you say, the permissibility of making a lying promise turns on a contingent empirical fact, namely on whether there is some third party ready to step in to ensure that even lying promises are fulfilled.

I am sure Kant and orthodox Kantians would not want morality to be like this. But ask yourself in conclusion whether such responsiveness to basic empirical facts about the world isn't actually an advantage in morality. Would it really be wrong falsely to promise repayment if such false promises were to hurt no one? And is it really implausible to hold (to give another example) that the question whether one is duty-bound to procreate depends on whether enough children would be born even without such a duty?

I'm also no scholar of Schopenhauer, but from what I remember he's claiming that our universe is at bottom non-rational -- fundamentally arising from causes rather than from reasons. The universe isn't, on this view, irrational if that means 'capable of reasoning but bad at it' or 'containing logical inconsistencies'. I take it that Schopenhauer is rejecting a theistic or deistic view that sees reason (and not causation) as fundamental to our universe. I agree with Professor Manter that neither Schopenhauer's view nor the view he's rejecting allows for inconsistent things such as square triangles.

Can I take this opportunity to grind an axe? Advocates of a supernatural (theistic or deistic) origin of our universe often claim that only their view -- rather than metaphysical naturalism -- gives us hope of achieving a rational understanding of the universe by investigating it. They say that only if the universe was rationally intended can we hope to understand it. I think the opposite is true. If the universe arose supernaturally, rather than by means that natural science could in principle explain, then we have no hope of understanding the universe ever more deeply by investigating it scientifically: we'll eventually hit a barrier beyond which there's literally just magic, something that by definition defies naturalistic explanation (and maybe any explanation). Only if the universe is fundamentally non-supernatural -- unintended, uncreated -- can we hope to delve ever deeper into it. A bit ironically, then, a Schopenhauer-like view of the universe as fundamentally non-rational is the one that gives us the best hope of understanding it rationally.

It's been years since I've read Schopenhauer, so I cannot respond with his position as such. What I am noticing is that you seem to have excluded other possibilities by assuming that if the universe is not rational it must be irrational. What about non-rational, for example? No squared circles needed!

If we posit that rationality is a capacity of human consciousness - and a mysterious thing consciousness is - what might it mean to call the universe "rational?" Are we saying it is conscious? Does the analogy to human consciousness hold sufficiently to apply to the vast universe? There might be human minds that see order and disorder and apply rational principles to their observations, but it is quite another thing to ascribe rationality to ... what? The universe is one of those concepts that is not a reality one can experience. Perhaps we can thank Schopenhauer (and his 19th century counterparts) for helping us see our anthropomorphizing for what it is.

Does this help? -bjm

Some random suggestions: (1) David Pears pointed out that even if Kant's argument were wholly clear and wholly successful, which it is not, it could only show that existence is not an ordinary predicate, if it is a predicate. His view is that it is a predicate, just a very peculiar one; (2) There is also the view of the celebrated logician, mathematician and philosopher Bolzano, who writes in the Theory of Science ("Kinds of Propositions") that 'I take being [Sein] or actuality [Wirklichkeit] to be precisely what language makes it out to be, namely an attribute; whoever denies this confuses (I believe) actuality with substance. By substance I mean an actuality which is not an attribute of another actuality; hence I admit that we cannot truly predicate the putative abstractum of the substance (substantiality) of any object. For it is part of the concept of substance that there is no property of this kind. But it is not the same with actuality, which I consider to be a mere attribute, not only of substance itself but of each of its attributes, since every attribute of an actual thing is itself actual. And since every attribute of an object can be ascribed to it in a judgment of the form 'A has b', why not the attribute of actuality?' (3) There is a related argument deriving from Russell's Theory of Descriptions in my own Philosophical Propositions, despite the fact that Russell himself took the implication of the theory to be that the ontological argument is no good; (4) There is a defence of a stripped-down version of the ontological argument by the late Gary Matthews and Lynn Baker Rudder in Analysis for 2010.

Sure. Even if existence is not a predicate, it's at least arguable that necessary existence is. (As Norman Malcolm pointed out years ago, there really are two versions of the argument, and the second one deals with necessary existence.)

We doubt that existence is a predicate because, roughly, saying that something exists tells us nothing about what it's like. Not so for necessary existence. Not just anything could exist necessarily. The computer I'm typing on is the wrong sort of thing to be a candidate for necessarily existing thing. Assuming that some things are of the right sort to exist necessarily, necessary existence would be a predicate.

Whether this is a defense of the argument all things considered is another matter. But I think the point made here is fair as far as it goes. A being that merely happened to exist wouldn't be a being than which none greater can be conceived.

Thank you for these interesting reflections! As for your first point, there are a number of philosophers who address radical skepticism (e.g. can any of us know with certainty that we are not, as we seem to be, wide awake and acting in the world rather than, say, dreaming?) in the way you suggest. Arguably, life may continue just as it appears until one's death and yet there would be no decisive reason to rule out the possibility one was merely a brain in a vat. And because of this, some philosophers think that such radical skeptical hypotheses are idle or nonsensical or of no interest. I am somewhat of the other mind: I think we can imagine radical hypothetical states of affairs in which we are indeed systematically mistaken in almost all our beliefs about ourselves in the world (in brief, I think it conceivable that we might be in the matrix). While this does not have awesome practical consequences, I think it should humble us in our knowledge claims. As for the second point, Quine set out to dismantle the very categorical distinction between the analytic and synthetic. Today, some think he was spot on, but there are large numbers of philosophers (including myself) who believe the analytic category is sensible and intelligible. I think it is an analytic truth that 1+1 equals 2 --based on the principle of identity or A is A (because 2 simply is '1+1' and so 1+1 equals 2 because 1=1 equals 1=1. You ask about explanations. On that point, things get quite interesting. The concepts of necessity, impossibility, and possibility can be explained in terms of one another. So the statement '1+1 = 2 is necessary' is equivalent to '1+1=2 is possible and 1+1 is not equal to 2 is not possible. To many of this, explanations like this are acceptable, but to some radical thinkers, such explanations are considered insufficient. For a great defense of the analytic category and the concepts at issue, check out Alvin Plantinga's classic On The Nature Of Necessity.

Plato calls in his Republic for women to participate as equals in the activities of citizenship, saying that surely many women are more excellent than some men and that less excellent women should be disqualified from various roles (along with less excellent males) on account of their lesser excellence rather than on account of their gender.

Good question! German idealism is so complex, but in general it may be said that phenomenology (as established by Edmund Husserl) was more bound to the study of appearances than, say, Hegel, even in his Phenomenology of Spirit. Hegel is prepared to think quite abstractly about being and nothingness, the rational and the real, and the dialectical movement of history (which we see Marx re-formatting), whereas Husserl's Cartesian Meditations is far more (for lack of a better word) experiential and involving the first-person. But interpreting Husserl and Hegel is not easy, and Husserl's book Ideas Pertaining to a Pure Phenomenology and Phenomenological Philosophy (1913) has been interpreted (I believe wrongly) as a traditional form of idealism. One minor point about your excellent question: some phenomenologists do not despair about the "thing-in-itself." There are what are known as phenomenological realists like Deitrich von Hildebrand who are committed to claims about the nature of the world (and the truths about the world and so on is not dependent upon experience, ideas, etc).

I used exactly this example in an essay published over 20 years ago as one of the arguments in support of a more subtle interpretation that had been first proposed by Tim Scanlon. On this reading, it is the permission one is claiming for oneself that is to be universalized. So instead of asking whether one can will that all people act on one's maxim of remaining childless, one is to ask instead whether one can will that all people be permitted to remain childless. In the world as it is, we can certainly will this universal permission (because enough others would decide to conceive even without a duty to do so), and therefore each of us is permitted to act on the maxim in question.