Russell, Experience, and the Roots of Science

A. C. Grayling

I

Empiricism is the family of theories which in one or another way locate the source or at very least the test of contingent knowledge in experience – specifically, in sensory experience. More circumstantially: it is the family of theories which variously require experiential grounds for concepts to have content or applicability, or for expressions in a given language to have sense. In these versions of a formulation, due allowance is made for the thought that the content of perceptual states, suitably construed, are to be considered the occasion or basis for certain kinds of fundamental judgments from which, together with other premises, our less fundamental judgments about the world (or things other than the content of those states of sensitivity themselves) can be inferred.

In a qualified sense of this broadly characterised position, Russell was an empiricist, and his epistemology remained in that qualified sense empiricist throughout its development. But he was also critical of certain forms of empiricism, and the focus of his own concerns were such that his aims in formulating epistemological views, and his evolving attempts to realise these aims in detail, are not straightforwardly traditional. The chief reason for this is that his overarching concern was the question of how science is related to subjective experience, beginning (in the work done in 1911-14) with attempts to show how the fundamental concepts of physics can be derived from experience, and ending (in 1948) by shifting attention to the question of the non-empirical features of knowledge-acquisition required for bridging the gap between experience and science.

In these aims for epistemology Russell was remarkably consistent throughout the period 1911- 48, which is to say, from the time he finished work on the first edition of PM until his last major philosophical book, HK. His concern was not the traditional epistemological one of showing that knowledge is justified by experience, where this task is typically specified by a response to sceptical arguments. Russell was thoroughly Lockean in his attitude to the theory of knowledge, in the sense that he did not think scepticism a serious option, and therefore did not waste time attempting to rebut it. Rather, he conceived epistemology's proper task as one of displaying how one gets from sense experience to science. For Russell this was an explanatory, not a justificatory, task.

In the cluster of texts addressing the question of the experience-science relation in the immediate post-PM period, Russell describes his aim as showing how physics is 'verified' by observation and experiment – by which he meant: having its predictions confirmed by these means. Given that all that can be directly observed are the data of sense, he saw the question as one of explaining the correlation of the contents of the physical world with the data of sensory experience by which they are alone verifiable . He did not put the point by saying that claims about the content of the physical world are verified (still less justified) by sensory experience; and this is neither an accidental nor a merely historically-conditioned trick of formulation. It is a feature of robust realism not to construe the point of epistemology as being the justification of knowledge-claims, but as being an explication of the relation between what the claims are about and the nature of experience. 'Justifying science by grounding it in experience' and 'showing how physics succeeds in being an empirical science, based on observation and experiment' are two different aims, and Russell's was the latter.

In PP, which gives the outlines of Russell's early view in popular form, the project begins by adopting the Cartesian air of a justificatory, scepticism-rebutting enterprise. The same is true of the discussion in IMT and Russell's replies in Schilpp. But that was because Russell saw the principal task of showing how experience and science relate as the obverse of the coin whose reverse is the more familiar form of discussion in which experience is invoked as the ground of knowledge. Because Russell assumed throughout that science is (or at least is on the way to discovering) the truth about the world (and his considered views consistently respected this assumption), he did not see epistemology's task to be the defence of science against doubt, but instead to be the demonstration of how finite human subjectivity acquires knowledge of the objective reality which science describes. In showing this, it also shows that the degree of certainty possible in contingent knowledge is less than absolute. In this sense, Russell was happy to concede something to scepticism without being much troubled by it; after all – so in effect he thought – what else is to be expected from contingent empirical knowledge.

In the earlier phases of his endeavour Russell saw the task of technical philosophy (philosophy conceived as logic; in fact, though, this aspect of Russell's endeavour is more accurately described as metaphysics) as principally being one of showing how the fundamental concepts of science (as he then took them to be) – space, time, causality and matter ­ can be constructed, and in his view this was a more important and more interesting matter than the epistemological question of how one relatively insignificant fragment of reality – humanity – manages more or less successfully to represent the rest of reality to itself. It is easy to overlook the fact that these two of Russell's tasks – the logical construction of the then-conceived fundamental scientific concepts, and the question of how finite subjective experience connects with scientific knowledge – are different, although of course they impinge upon one another at most points. But Russell's attention came rapidly to focus almost exclusively on the epistemological task, to which the larger part of his strictly philosophical writings after 1911 were addressed.

What changed over time in Russell's thought after 1911 was not his epistemological aim, but the strategies he successively adopted to try to achieve it. Perhaps because science itself dramatically altered the question of which concepts are fundamental to it (space and time had become space-time in Einstein's theories, and matter had vanished in the wake both of them and quantum theory), Russell ceased to look for a logical construction of these specific concepts. Indeed, he abandoned the logical constructivist programme long before the likes of Carnap and Goodman attempted them, and before Wisdom had shown that getting the world out of sense-data without residue is impossible.

The continuities and developments in Russell's relation-of-sense-to-science project are well displayed as the similarities and contrasts between his description of the project's aims, and of the methods to be employed in carrying it out, in the 1911-14 writings and HK in 1948. Commentators generally take at face value Russell's own claim, in MPD, that in AMi (1921) he abandoned not just the nomenclature of the sense-datum theory but what it was trying to achieve; and this is taken among other things to mark a more expressly 'neutral monist' turn as the metaphysical basis of his epistemological efforts until, in his very late work, another and final shift of perspective occurs, this time away from efforts to carry out the original project and towards the task of identifying the non-empirical supplements which, by that stage, he saw as the chief interest in discussing the bridge over the experience-science gap. But in fact it can be shown that despite the asseverations of MPD and the apparent elimination of the subject in AMi (courtesy of Russell's by then further developed conception of the 'neutral monist' stance), the underlying theme of specifying the connections between experience and science remained. Of course, from the period of AMi onward Russell changed the terms of the relation at issue dramatically; acquaintance vanished, and was replaced (to begin with) by 'noticing' (experiential salience) and successor conceptions. Acquaintance and the subject seemed to go so intimately together that their departure appeared jointly necessary; but it is no surprise to find the epistemic subject still in view in HK, having been merely in disguise in the interim.

The purpose in what follows is accordingly to illustrate, by way of an account of the development of Russell's project, the remarkable consistency of aim it displays. I do this by tracing the project's history, chiefly to establish an accurate characterisation of it, but also to provide a corrective to the impression that in epistemology Russell merely offered a sequence of ad hoc moves in response to a problem which has since been understood, but even then was already beginning to be recognised, as misconceived, viz. the endeavour to erect a justificatory theory of knowledge on the flawed Cartesian grounds of deriving certainty from the private data of experience. But to repeat: Russell's task was, interestingly and significantly, different from that; he did not see epistemology as a justificatory enterprise aimed at refuting scepticism, but as a descriptive enterprise aimed at explaining the fact (which he did not question) that finite subjects attain scientific knowledge. He was thus a naturalist long before Quine or anyone else, despite rightly insisting, as later naturalists did not, that one cannot premise science in epistemology ; and he was far more consistent in his aims and principles than most (agreeing with Charles Broad ) have allowed.

Certain corollaries attend the picture I offer. One is that Hylton misdescribes Russell's turn to epistemological themes after PM as involving 'considerable concessions to psychologism'. Whatever else the label means, 'psychologism' is at least the view that the objects of acquaintance and judgment (to use period Russellian terms for the purpose) cannot themselves be described independently of features attaching to them as a result of the psychological conditions of their apprehension. This is never Russell's claim, and indeed anything like it was expressly disavowed in his pre-PoM flight from idealism. Post-PM Russell was realist to excess, rather than psychologistic, in allowing a wider range of objective targets of acquaintance than a traditional empiricist would allow, embracing as it did both physical particulars and abstract entities of various kinds. So much is familiar. And this is not to deny that Russell's interests lay in connecting the content of psychological states (mental states of the subject-relatum in acquaintance and judgment) with the independent objects such states brought into the subject's ken; for, after all, it was the 'transition from sense to science' as he still called it at the end of his philosophical life (MPD 153) that was his focus, and this requires addressing the question of what and how much the psychological states of epistemic subjects can be said to give them of objective scientific truth.

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