There is an image - found in Boethius, Dante and elsewhere - of God's view of the universe being somewhat like that from a high mountain, with all time being laid out on a great plain below so that past and future are simultaneously visible to the divine eye. This "eternalist" conception immediately raises the question of free will. It also illustrates our general tendency to think of time in spatial terms, even in everyday speech: for example "passing" time during a "long" lecture by "going over" something in our head, "thinking back" on past events, "looking forward" to future ones, and so on. Against this spatial conception of time, and the eternalism it implicitly invites, Henri Bergson (1859-1941) mounted a vigorous and, to my mind, strikingly persuasive protest that gained great attention in his lifetime, but suffered a posthumous eclipse. In the introduction to Deleuze's Bergsonism (French edition 1966, English translation 1988), the translator wrote, "Although Henri Bergson was one of the most important and widely read philosophers of the first decades of the twentieth century, nowadays his work seems to be almost forgotten." Deleuze helped stimulate a revival that has continued, with particular interest centring on Bergson's idea of "multiplicity".
Bergson's father was a Polish Jewish concert pianist (perhaps explaining Bergson's fondness for musical/aural analogies), while from his London-born mother he acquired fluency in English. Bergson showed outstanding promise in mathematics but opted for philosophy with particular interest in psychology: his first published article was on hypnosis. This concern with psychology is reflected in the French title of his 1899 doctoral thesis, Essai sur les données immédiates de la conscience, while the English title, Time and Free Will (henceforth TAFW) highlights an application of his analysis of mental states for which he would become particularly well known. Bergson's ideas were of interest to literary figures including Proust (whose cousin Bergson married in 1891) and T.S. Eliot (who attended his lectures in Paris in 1911), while the enthusiasm of William James helped cement his international reputation. He was nominated for the Nobel Prize for literature in 1912 and eventually won it, on his eighth nomination, in 1927. A celebrated public intellectual, he was also active in politics and diplomacy. According to some sources it may have been while queuing to register as a Jew in occupied France (despite having been excused) that he caught the cold that led to his death.
As a philosopher, Bergson is a dualist: he acknowledges the independent existence of matter in external space, as well as non-material "psychic states" whose multiplicity constitute our conscious being. Alongside this duality there is another, that of quality versus quantity. Bergson's key notion is that space and matter are quantitative whereas psychic states are qualitative. From this there follows (eventually) his famous concept of durée, the "duration" of the self in contrast to external time.
In the first chapter of TAFW he asks us to imagine taking a pin in our right hand and pressing its point onto our left. As we exert increasing pressure with the right hand we feel growing pain in the left. The muscular force of the right hand is objectively quantifiable: we could even set up a device to measure how hard we press at each moment. This leads us to suppose that the resulting pain in the left is likewise quantifiable, a certain amount of pressure producing a corresponding quantity of pain. Bergson however says that instead of an increase of sensation there is a sensation of increase. What we actually experience is a succession of qualitatively different psychic states. A tickle might become an insistent push, a nagging itch, a discomfort provoking tension which spreads throughout our body. Bergson insists on a further important dualism: the external pressure is "homogeneous" while the psychic states are "heterogeneous". At one instant the pinprick might amount to, say, ten pressure-units, while a minute later it has increased to twenty units. We could say with confidence that there was an intervening moment when the quantity was fifteen pressure-units, and we can measure exactly when it reaches any chosen amount. The psychic states cannot be isolated in this way: they merge and overlap, and do not form a separable series. They are a "confused qualitative multiplicity" in contrast to the "quantitative multiplicity" of the applied pressure. The external stimulus is repeatable: a pinprick of ten units is the same thing every time it is applied, and this repeatability is essential to the quantification. Yet the resulting psychic states are unique: when you prick your finger tomorrow you will not be the same person that you are today.
Nevertheless we suppose our pain to be quantified, and in this way we "project" something of our qualitative self onto the external world. This is a kind of loss, though it is also the basis for communication and socialisation (Bergson conjectures it to be a faculty lacking in animals). To quantify anything, Bergson claims, it must be imagined as existing in space: the rising pressure of the pin is represented as an ascending line on a chart, say, or a moving needle on a dial, or a mental series of points on a number-line. We externalise our deep self by projection onto homogeneous space, but at the same time our knowledge of the external world comes from its impact on our psychic states. There is thus a meeting and intermingling ("endosmosis"), and we mostly live at the boundary between quality and quantity, heterogeneity and homogeneity, inhabiting what Bergson considers to be a kind of "surface" self. It is only through rigorous intuition that we can appreciate what lies "beneath": a metaphor, we notice, that is itself spatial. Words, numbers and indeed the whole material world can only ever be "symbols" of a qualitative self that is inherently inexpressible.
Spatial thinking makes it possible for us to quantify and rationalise reality: we can do science. But spatial thinking robs us of a true appreciation of psychic states. External time, quantified by clocks, must correspond to some inner counterpart to be sought through introspection.
We could do an experiment where people are asked to estimate how much time has passed during some task they are set (we all know that boring tasks feel long while exciting ones pass quickly). All we would then be doing is quantifying the experience of time; the same thing we thought of in relation to the pinprick. This would be a contribution to psychophysics, the scientific discipline founded by Gustav Fechner, which Bergson critiques in TAFW. Psychophysics is perfectly valid as science, but takes us no closer to understanding the qualitative counterpart to quantified time. This inner counterpart must (if we accept Bergson's premises) be a heterogeneous multiplicity; in other words it will not consist of distinct separable moments, except to the extent that we perceive it on our surface self. It will be a succession of unrepeatable, intermingling states. This is "duration".
To contrast duration with time, Bergson asks us to imagine what it would be like if every temporal process were suddenly to proceed twice as fast. Would we notice any difference? If the only kind of time that exists is quantifiable clock-time, then our minds would be accelerated along with everything else, and we would see nothing different. In that case the "flow" or "rate" of time has no objective meaning, no place in science. Yet this "flow" is, from our point of view, a fundamental feature of what we think of as time. The sensation of flow must be a psychic state, qualitative rather than quantitative. Duration therefore exists only through being "lived": we "endure" (experience duration) while external objects only appear to. With the pinprick we mistook a sensation of increase for an increase of sensation; in the way we normally think of time we mistake our sensation of flow for something quantifiable and external. We mentally project duration onto space and imagine time to be a homogeneous medium: a "fourth dimension" through which things "move". (Notice, incidentally, a confusion of language that potentially adds to the conceptual confusion: in space we measure distance but in "time" - conceived as homogeneous medium - we measure "the time").
Bergson wishes to show why it is wrong to imagine time as a homogeneous medium like space. He does this by analysing the process of measurement. If I want to measure the length of a table I can put a tape against it and read the numbers at either end. I juxtapose two objects in space (tape and table) and inspect two points (the table ends) simultaneously. But I can never bring together two moments of time: one goes away and another comes. Only the present exists, and all I can measure are simultaneities. My watch says twelve o'clock when I order lunch and one thirty when I pay the bill, and by subtraction I deduce that my meal lasted ninety minutes. I mentally picture successive moments on a timeline, and from that I make the conceptual leap to suppose that time itself is a kind of space. But that is an abstraction, not a reality, and if we take the abstraction literally we are led into the problem of determinism and free-will. Remove the illusion of time as homogeneous medium, says Bergson, and the problem vanishes.
For Bergson, freedom itself cannot be defined, but is an essential feature of our deep self, reflecting the uniqueness of psychic states. Mostly we do not act freely; we live at the surface, between quality and quantity, and it is only in rare and notable moments that we reach into our core and become truly liberated.
The extract (pp124-137) can be considered a continuation and elaboration of the foregoing remarks.