In this paper I put forward a suggestion for identifying causality in micro-systems with the specific quantum field theoretic interactions that occur in such systems. I first argue — along the lines of general transference theories — that such a physicalistic account is essential to an understanding of causation; I then proceed to sketch the concept of interaction as it occurs in quantum field theory and I do so from both a formal and an informal point of view. Finally, I (...) present reasons for thinking that only a quantum field theoretic account can do the job — in particular I rely on a theorem by D. Currie and to the effect that interaction cannot be described in (a Hamiltonian formulation of) Classical Mechanics. Throughout the paper I attempt to suggest that the widespread scepticism about the ability of quantum theory to support a theory of causality is mistaken and rests on several misunderstandings. (shrink)

The ability to imagine objects undergoing rotation (mental rotation) improves markedly with practice, but an explanation of this plasticity remains controversial. Some researchers propose that practice speeds up the rate of a general-purpose rotation algorithm. Others maintain that performance improvements arise through the adoption of a new cognitive strategy—repeated exposure leads to rapid retrieval from memory of the required response to familiar mental rotation stimuli. In two experiments we provide support for an integrated explanation of practice effects in mental rotation (...) by combining behavioral and EEG measures in a way that provides more rigorous inference than is available from either measure alone. Before practice, participants displayed two well-established signatures of mental rotation: Both response time and EEG negativity increased linearly with rotation angle. After extensive practice with a small set of stimuli, both signatures of mental rotation had all but disappeared. In contrast, after the same amount of practice with a much larger set both signatures remained, even though performance improved markedly. Taken together, these results constitute a reversed association, which cannot arise from variation in a single cause, and so they provide compelling evidence for the existence of two routes to expertise in mental rotation. We also found novel evidence that practice with the large but not the small stimulus set increased the magnitude of an early visual evoked potential, suggesting increased rotation speed is enabled by improved efficiency in extracting three-dimensional information from two-dimensional stimuli. (shrink)

Discrete choice experiments—selecting the best and/or worst from a set of options—are increasingly used to provide more efficient and valid measurement of attitudes or preferences than conventional methods such as Likert scales. Discrete choice data have traditionally been analyzed with random utility models that have good measurement properties but provide limited insight into cognitive processes. We extend a well-established cognitive model, which has successfully explained both choices and response times for simple decision tasks, to complex, multi-attribute discrete choice data. The (...) fits, and parameters, of the extended model for two sets of choice data (involving patient preferences for dermatology appointments, and consumer attitudes toward mobile phones) agree with those of standard choice models. The extended model also accounts for choice and response time data in a perceptual judgment task designed in a manner analogous to best–worst discrete choice experiments. We conclude that several research fields might benefit from discrete choice experiments, and that the particular accumulator-based models of decision making used in response time research can also provide process-level instantiations for random utility models. (shrink)

My paper, written in 1911, was something of a ballon d'essai, and I acknowledge frankly one or two mistakes. Thus I did not know that Euripides wrote a Thyestes; and again one or two of my references were wrong: in excuse I may perhaps plead that I have not had access to a Latin book for nearly two years. Apart from this I will now make only two observations:1. I set aside the evidence of Cod. Paris. Lat. 7530 because I (...) was dealing with evidence of saec. i.-iv. Cod. Paris. Lat. 7530 shows that some persons at the end of saec. viii. ascribed the Thyestes to L. Varius Rufus. So did persons in saec. iv. In addition, Cod. Paris. Lat. 7530 gives a date for the Thyestes. To Mr. Housmanthis date is certain; if it is uncertain a large part of his argument comes to nothing. But who can think it certain ? It comes to us from the end of the eighth century. If it came to us from Jerome's Chronicle we could still not think it certain, though we should know whence Jerome derived it. We do not now whence Cod. Paris. Lat. 7530 derived it. The reference to Actium may have no better source than the wish to connect a great literary and a great political event: and the gossip about the playwright's profits seems to me in itself suspicious.2. The main contention of the early part of my paper was that the evidence of the relevant MSS. as between Vari and Varii, etc., amounts to nothing either way. I do not think Mr. Housman is prepared seriously to contest this proposition. (shrink)

Desmosomes are junctions involved in intercellular adhesion of epithelial cells and hemidesmosomes are junctions involved in adhesion of epithelia to basement membranes. Both are characterised at the ultrastructural level by dense cytoplasmic plaques which are linked to the intermediate filament cytoskeleton of the cells. The plaques strongly resemble each other suggesting a relationship between the two kinds of junctions, as implied by their names. Recent characterisation of the molecular components of the junctions shows they are, in fact, quite unrelated implying (...) that structural similarity is fortuitous. The molecular biology raises many fascinating problems relating to their structure and function. (shrink)

Pickering & Garrod deserve appreciation for their cogent argument that dialogue merits greater scientific consideration. Current models make little contact with behaviors of dialogue, motivating the interactive alignment theory. However, the theory is not truly “mechanistic.” A full account requires both representations and processes bringing those representations into harmony. We suggest that Grossberg 's adaptive resonance theory may naturally conform to the principles of dialogue.

It’s a truism of philosophy that Realists must not postulate more than we could reasonably hope to know, while Anti-Realists must not leave us with so little that all knowledge is impossible. But balance is not easily come by—and even less in philosophy than in life. So philosophy continues to struggle over the hard cases, with neither the Realist nor the Anti-Realist able to score an easy victory.

An extensive survey by Heathcote et al. (in press) found that the Law of Practice is closer to an exponential than a power form. We show that this result is hard to obtain for models using leaky competitive units when practice affects only the input, but that it can be accommodated when practice affects shunting self-excitation.

The purpose of this article is to show that the truthmaker solution to the Gettier counter-examples can solve the Russell case of the stopped clock (other standard cases have already been analysed). The solution amounts to this: the truthmaker for the claim that it is, say, 2.00 pm, is a combination of natural and non-natural determinants. The latter are created by stipulation, but having been so made make it is a perfectly objective matter as to whether it is 2.00 o'clock. (...) To know that it is 2.00 pm is to have the evidence for one's belief evidence of the very state of affairs that make the belief true. Thus, in the Russell case one does not have knowledge, in accord with intuition. (shrink)

The indistinguishability of bosons and fermions has been an essential part of our ideas of quantum mechanics since the 1920s. But what is the mathematical basis for this indistinguishability? An answer was provided in the group representation theory that developed alongside quantum theory and quickly became a major part of its mathematical structure. In the 1930s such a complex and seemingly abstract theory came to be rejected by physicists as the standard functional analysis picture presented by John von Neumann took (...) hold. The purpose of the present account is to show how indistinguishability is explained within representation theory. (shrink)

The significance of Max Black’s indistinguishable spheres for the nature of particles in quantum mechanics is discussed, focusing in particular on the use of the idea of weak indiscernibility. It is argued that there can be four such Black spheres but that five are impossible. It follows from this that Black’s example cannot serve as a model for indistinguishability in physics. But Black’s discussion of his spheres gave rise to the idea of weak discernibility and it is argued that such (...) predicates are unsatisfiable in the way intended. The underlying problem with weak discernibility spreads out to also undermine the whole notion that indistinguishability rests on a notion of the permutation invariance of particles. A better foundation is indicated. (shrink)

There is a large literature on the issue of the lack of properties (i.e. accidents) in quantum mechanics (the problem of “hidden variables”) and also on the indistinguishability of particles. Both issues were discussed as far back as the late 1920’s. However, the implications of these challenges to classical ontology were taken up rather late, in part in the ‘quantum set theory’ of Takeuti (Curr Issues Quant Logic 303–322, 1981), Finkelstein (in Beltrametti EG, Van Fraassen BC (eds) Current issues in (...) quantum logic. Plenum, New York, 1981) and the work of Décio Krause (1992)—and subsequent publications). But the problems created by quantum mechanics go far beyond set theory or the identity of indiscernibles (another subject that has been often discussed)—it extends, I argue, to our accounts of truth. To solve this problem, i.e. to have an approach to truth that facilitates a transition from a classical to a quantum ontology one must have a unified framework for them both. This is done within the context of a pluralist view of truthmaking, where the truthmakers are unified in having a monoidal structure. The structure of the paper is as follows. After a brief introduction, the idea of a monoid is outlined (in Sect. 1) followed by a standard set of axioms that govern the truthmaker relation from elements of the monoid to the set of propositions. This is followed, in Sect. 2, by a discussion of how to have truthmakers for two kinds of necessities: tautologies and analytic truths. The next Sect. 3, then applies these ideas to quantum mechanics. It gives an account of quantum states and shows how these form a monoid. The final section then argues that quantum logic does not, despite what one might initially suspect, stand in the way of an account of quantum truth. (shrink)

A proof is presented that a form of incompleteness in Quantum Mechanics follows directly from the use of unbounded operators. It is then shown that the problems that arise for such operators are not connected to the non- commutativity of many pairs of operators in Quantum Mechanics and hence are an additional source of incompleteness to that which allegedly flows from the..

Mathematics, as Eugene Wigner noted, is unreasonably effective in physics. The argument of this paper is that the disproportionate attention that philosophers have paid to discrete structures such as the natural numbers, for which a nominalist construction may be possible, has deprived us of the best argument for Platonism, which lies in continuous structures—in fields and their derived algebras, such as Clifford algebras. The argument that Wigner was making is best made with respect to such structures—in a loose sense, with (...) respect to geometry rather than arithmetic. The purpose of the present paper is to make this connection between mathematical realism and geometrical entities. It thus constitutes an argument against formalism, for which mathematics is merely a game with humanly set rules; and nominalism, in which whatever mathematics is used is eliminable in the final analysis, by often insufficiently specified means. The hope is that light may be cast on the stubborn mysteries of the nature of quantum mechanics and its mathematical formulation, with particular reference to spinor representations—as they have been developed by Andrej Trautman. Thus, according to our argument, quantum mechanics (QM) may appear more natural, as we have better reasons to take spinor structures as irreducibly real, a view consonant with the work of Trautman and Penrose in particular. (shrink)

The Received View of particles in quantum mechanics is that they are indistinguishable entities within their kinds and that, as a consequence, they are not individuals in the metaphysical sense and self-identity does not meaningfully apply to them. Nevertheless cardinality does apply, in that one can have n> 1 such particles. A number of authors have recently argued that this cluster of claims is internally contradictory: roughly, that having more than one such particle requires that the concepts of distinctness and (...) identity must apply after all. A common thread here is that the notion of identity is too fundamental to forego in any metaphysical account. I argue that this argument fails. I then argue that the failure of individuality and identity applies also to macroscopic physical objects, that the problems cannot be constrained to apply only within the microscopic realm. (shrink)

That there is an edge at all is, of course, philosophically controversial; it would be denied by anti-realists of a verificationist stripe. However, we accept, since G¨odel, that there are true propositions of elementary arithmetic that are unprovable in arithmetic; just so, we should accept—by analogy—that there are true statements that are unknowable. An argument called the Fitch Argument tells us that it is so. Williamson has long argued that the Fitch Argument cannot by itself refute antirealism—because the anti-realist is (...) already committed to the denial of some of the principles of classical logic required to derive the anti-realist conclusion. The point is well made.1 In Knowledge and its Limits, however, Williamson looks at what the Fitch argument tells us if we adhere to classical logic: and that is that there are unknowable truths. (shrink)

The geometric mean is also called the mean proportional. This is how the mathematicians of the √ −1. 19th Century, such as Gauss, understood..

It is argued that the part-whole account of the relation between evidence and the larger state of affairs the evidence is evidence of—an account that was elucidated in the paper ‘Truthmaking, Evidence of, and Impossibility Proofs’ —provides a better basis for epistemology than causal relations between events. I apply this to a well-known phenomenon in physics which suggests that causal connectedness is not necessary for knowledge.

In his essay ‘Laws and States in Quantum Mechanics’, John Forge presents a case for considering laws of nature to be privileged sets of states, trajectories in the quantum mechanical analogue of phase space. Having presented an argument to show that states have to be taken with full ontological seriousness, Forge then uses those states to undergird his favourite account of laws and explanation — called the Instance View. On this view laws are a special sort of pattern, a certain (...) kind of regularity, and explanations are instances of these regularities (so that you explain some phenomenon A by indicating that it is an instance of some regularity R). Forge then uses this account of laws and explanation to urge the acceptance of van Fraassen’s Modal Interpretation of Quantum Mechanics. (shrink)

Beginning with Zagzebski (The Philosophical Quarterly 44:65–73, 1994), some philosophers have argued that there can be no solution to the Gettier counterexamples within the framework of a fallibilist theory of knowledge. If true, this would be devastating, since it is believed on good grounds that infallibilism leads to scepticism. But I argue here that these purported proofs are mistaken and that the truthmaker solution to the Gettier problems is both cogent and fallibilist in nature. To show this I develop the (...) notion of evidence of a state of affairs, a crucial concept in the truthmaker theory. I also argue that a common principle of the transmission of evidence through entailment is false, and the cause of much of the trouble. (shrink)