Local orientational ordering in fluids of spherical molecules with dipolar-like anisotropic adhesion

We discuss some interesting physical features stemming from our previous analytical study of a simple model of a fluid with dipolar-like interactions of very short range in addition to the usual isotropic Baxter potential for adhesive spheres. While the isotropic part is found to rule the global structural and thermodynamical equilibrium properties of the fluid, the weaker anisotropic part gives rise to an interesting short-range local ordering of nearly spherical condensation clusters, containing short portions of chains having nose-to-tail parallel alignment which runs antiparallel to adjacent similar chains.Comment: 13 pages and 6 figure

That Useless Time Machine

It is not our practice to raise complaints against a negative review report. We believe in peer refereeing and we respect it, whatever its content and consequences. However, in the case of our latest grant application (project named ‘The Time Machine’) we find it necessary to express our astonishment at the motivations with which our request for funding was turned down. Your main objection appears to be that our project is ‘philosophically interesting’ but ‘practically useless’, by which you mean that the project ‘has no potential for applications.’ We do not quite think that the main criterion for judging the scientific value of a project should be its practical usefulness, but never mind that. Let us agree that usefulness is a relevant criterion, especially when large amounts of money are involved. Why should that be a reason to turn down our project? Quite frankly, we cannot think of a project with better application potential than ours. Certainly you have noticed that our suggestions for practical applications of the time machine did not include any uses that could result in an alteration of the natural course of history. As a matter of fact, we believe that no such alteration is logically possible. According to our project, it is logically possible to visit the past but not to modify the past. No time traveler can undo what has been done or do what has not been done. So the logic is safe

The Naming of Facts

"The naming of facts is a difficult matter / it isn’t just one of your holiday games / You may think at first I’m as mad as a hatter / When I tell you, a fact may have TWO DIFFERENT NAMES." A versification of a disturbing philosophical tribulation, after T. S. Eliot’s ‘The Naming of Cats

The Vagueness of ‘Vague’: Rejoinder to Hull

Is ‘vague’ vague? Why so much fuss about a single word? One reason, I think, is that a lot depends on how we settle the question. For example, Frege famously remarked that logic must be restricted to non-vague predicates. But if ‘vague’ is vague, then so is ‘non-vague’, hence the restriction is itself vague and, therefore, helpless. For another example, incoherence theorists such as Unger have claimed that vague terms have no clear instances, blocking the sorites paradox at the base step. If ‘vague’ is vague, however, then either it is a clear instance of itself, in which case the incoherentist claim is plainly false, or it has an empty extension, in which case the claim is vacuously true (there are no vague predicates) and the paradox strikes back. Finally, if ‘vague’ is vague, then—as Hyde has argued—vague predicates must suffer from the phenomenon of higher-order vagueness (at least some must, if Tye is right). So I agree with Hull: this is no small issue and we need to look at it closel

Event Location and Vagueness

That our event talk is vague is no news. Unlike facts, events are particulars located in space and time. But in ordinary circumstances it is utterly difficult, if not impossible, to specify the exact extent of the relevant spatiotemporal location. We say that Brutus stabbed Caesar and we intend to refer to an event — Brutus’s stabbing of Caesar—that took place at a certain time in a certain place. It took place in the Senate (not in the Coliseum) during the Ides of March (not April) in Rome, 44 BC. But where exactly in the Senate did this event take place? Did it spread only through Brutus and Caesar? Did it spread through their entire bodies? (Was Brutus’s left ear involved at all in this event?) Did it also spread through some space between them? Through what portion of space? And when exactly on March 15 did the killing begin? When exactly did it end? We don’t think the difficulty here is purely epistemic, as if it were just a matter of ignoring the facts. It’s not that there is this event, Brutus’s killing of Caesar, that has perfectly precise and yet unknown spatiotemporal boundaries, boundaries that historians have not been able (and will never be able) to locate. It’s not that such events as the industrial revolution, the discovery of penicillin, or World War II have precise and unknown spatiotemporal boundaries whose location eschews us. The indeterminacy here is not epistemic, or so we claim. Does it follow that the indeterminacy is ontological—that events such as these have fuzzy spatial or temporal boundaries? We don’t think so, either

Change, Temporal Parts, and the Argument from Vagueness

The so-called ‘argument from vagueness’ is among the most powerful and innovative arguments offered in support of the view that objects are four-dimensional perdurants. The argument is defective – I submit – and in a number of ways that are worth looking into. But each ‘defect’, each gap in the argument, corresponds to a model of change that is independently problematic and that can hardly be built into the common-sense picture of the world. So once all the gaps of the argument are filled in, the three-dimensionalist is left with the burden of a response that cannot rely on a passive plea for common sense. The argument is not a threat to common sense as such; it is a threat to the three-dimensionalist faithfulness to common sense

Mereological Commitments

We tend to talk about (refer to, quantify over) parts in the same way in which we talk about whole objects. Yet a part is not something to be included in an inventory of the world over and above the whole to which it belongs, and a whole is not something to be included in an inventory over and above its own parts. This paper is an attempt to clarify a way of dealing with this tension which may be labeled the Minimalist View: an element in the field of a part-whole relation is to be included in an inventory of the world if, and only if, it does not overlap any other element that is itself included in the inventory. As it turns out, a clarification of this view involves both a defense of mereological extensionality and an account of the topological distinction between detached and undetached parts (and the parallel opposition between scattered and connected wholes)

Beth Too, but Only If

Today’s test will be on the conditional connective. As always, I will just give you a sentence in English and you will have to symbolize it in the language of sentential logic. Remember that symbolization is a procedure whereby you extract the logical form of a sentence. This is not just a translation procedure and there is no straightforward algorithm for it; it sometimes involves a difficult process of interpretation. But it is crucially important for logic, for the logical techniques that we are going to develop will apply to well-formed formulas of the language of sentential logic and only indirectly to the sentences of English. It will apply, that is, to the logical forms of the sentences of English

Reasoning about space: The hole story

Much of our naive reasoning about space involves reasoning about holes and holed objects. We put things in holes, through holes, around them; we jump out of a hole or fall into one; we compare holes, measure them, enlarge them, fill them up

Topological Essentialism

This paper analyses topological variants of mereological essentialism, the thesis that an object cannot have different parts than the ones it has. In particular, we examine de dicto and de re versions of two theses: (i) that an object cannot change its external connections (e.g., adjacent objects cannot be separated), and (ii) that an object cannot change its topological genus (e.g., a doughnut cannot turn into a sphere). Stronger forms of structural essentialism, such as morphological essentialism (an object cannot change shape) and locative essentialism (an object cannot change position) are also examined