research project funded by the SNSF (100011-126656), 10.2010-9.2013 (TBC)
We live in a world of middle-sized dry physical objects, moving with more or less constant mass and average velocity, persisting in time and undergoing moderate and gradual change. We take these objects to be substances, entities possessing an inner nature possibly unknown to us, and exemplifying intrinsic properties. We assume that these objects have stable identity conditions, and can be individuated separately from each other. We take it for granted that most of these objects are composed of smaller parts, and that their mode of composition bestows them with an inner structure and identifiable properties.
Modern science has radically challenged these assumptions. Physics tells us that time is a much stranger phenomenon than anyone ever imagined. Special relativity tells us that our watches run slower if we travel quickly, and general relativity permits travel not only forward and backward in space, but also backward in time. Fundamental physical laws are typically time-reversible, and thus cannot underpin any asymmetry in the ordering of our experiences. Time-reversibility seems to flatly contradict how we see the world and ourselves – plainly, my birth and my death are very different things to me.
Contemporary, and admittedly more speculative, attempts at unifying the general theory of relativity and the other pillar of modern physics, quantum mechanics, entail an even more puzzling - and disturbing - claim: time is not even a fundamental physical magnitude according to one of the two major approaches to such a unification. Put differently, there is no longer a fiducial time with respect to which any evolution can be understood to happen. There seems to be no change whatsoever at the most fundamental level of nature!
Not just our ordinary conceptions of time and change have become fundamentally challenged by modern physics, but physics also tell us that the things persisting in time and undergoing change are very different from what we usually think. Some physicists even deny that there are any such things at all. We ordinarily think of objects, particulars, or substances as things that have individuating identity conditions – clearly it is one thing to be this table, and another thing to be another table, perhaps perfectly similar to this one, but still a different, and independent object. We think of things like tables as having possibly hidden essences: in the same way we cannot see the table simultaneously from all sides, we can never be sure that we know all about it. Explaining its macrophysical properties, its behaviour under stress or its heating potential require complicated bridge laws stating how specific configurations of microphysical properties give rise to such higher-level characteristics under certain circumstances.
Physics tells us that the fundamental building blocks of the universe are very different from tables: they have very few, if any, intrinsic properties and come in homogeneous kinds, with little to distinguish different members. Take two electrons in the orbital of a helium atom: they have the same energy eigenstate and the same position state, and still they are two – how that? In fact, we can show that they are two, because we can show that they have opposite spins. They are indiscernible by monadic predicates, but satisfy a binary irreflexive relation (of having opposite spin to), hence there must be two, and hence, in some sense at least, they are two objects . But it is not just that we cannot distinguish them, rather there is nothing to there being one of these two electrons rather than the other. They are not just identified purely relationally, but they themselves seem nothing else than nodes in a network of relations. But can we go from there to the "wholesale abandonment of the ... intuition that there must be something of which the world is made", as some philosophers have recently claimed (Ladyman/Ross 2007: 12)?
Philosophers are in the business of developing a coherent world view. They are thus left with the task of reconciling two apparently incompatible demands: to respect the claims of modern science, and also to respect the so-called "Moorean facts" of common sense which inform our conception of ourselves and of the world in which we act. Success in this endeavour is of the utmost importance, not just because science without philosophy (i.e. critical reconceptualisation of its results) is blind, while philosophy without science is empty (to adapt a famous saying of Kant’s), but also because the extravagant claims of modern science raise suspicions and fears. To counter this growing anti-scientific skepticism, the claims of science about fundamental reality have to be understood much better. We urgently need (i) a theory of what it means to be fundamental; (ii) some understanding of the nature and structure of the relation the more fundamental bears to the less fundamental; (iii) an account of what is fundamental, taking into consideration contemporary science.
The key idea of this research project is to approach the above mentioned problem of reconciling science and common sense from an unexpected angle. Presumably, relativity theorists do not want to say that their lives could have started with their death and ended with their birth, no more than researchers in loop quantum gravity want to say that nothing ever changes (their own scientific careers included). No one seriously denies that, in some sense at least, there are tables and other persisting objects that undergo change. But the following seem to capture what those who derive astonishing claims from basic science have in mind:
It is not clear, however, what "Fundamentally, such-and-such is the case." means. Does it, for example, imply that such-and-such is the case? If it does, then what does it add to say that such-and-such is not just the case, but fundamentally the case? If it does not, then which of the things that are not the case, are still fundamentally the case?
But even if this prior question were answered, the notion of fundamentality would remain problematic. What is the relation between the more and the less fundamental? Does the less fundamental reduce to, supervene on, or depend on the more fundamental? Can, or must, it be explained in terms of the more fundamental? Is it "nothing over and above", or does it have its own existence? Is it somehow less important, perhaps even dispensable in a description of the world?