Light, Space, Time and Beauty – Elements of a Philosophy of Light Nikos Psarros, Leipzig 1. The Privileged Position of Light and Vision in Nature In the biblical narration, light was the first concrete entity that was called into existence with an 1 explicit command: fiat lux! Although God had already created heaven and earth before the creation of light, there is no detailed narration about their creation or their constitution, just the report: “In the beginning God created the heavens and the earth. The earth was without form and void, and darkness was upon the face of the deep; and the Spirit of God was moving over the face 2 of the waters”. The completion of the world as a place where man can live and thrive was undertaken after the creation was immersed in light and the cycle of night and day began. The privileged position of light in the narration of Genesis, as well as in other cosmogonical narra3 tions, reflects its special position in the physical and aesthetic reality. Light is necessary for life as we experience it, and vision, the sense with which we perceive the existence of light and its various aspects – colours, shapes, and movements – is unique among our senses. Vision is namely the simplest sense because it is the only one that does not involve any direct interaction of the sense organ with a material or a material property, such as density or chemical composition, in order to operate. The visibility of an object relies only on a single property of any material, its transparency 4 to light. A transparent material does not interact with the sense organ of vision; it acts only as a medium of propagation of light, which is the only material requirement for the operation of vision. The other senses require a more concrete interaction with the material world: audition relies on the density of the air or any other kind of matter, in which sound can propagate. Olfaction and gustation require the intake and the physiological processing of material in order to produce the corresponding sensations, and finally tactition works only upon the direct mechanical contact with the sensed object. Despite being the simplest sense, vision enables nevertheless the most complex perception of the 5 world because vision has the highest “dimensionality”: The field of vision is two-dimensional (width and length) and each point in it is characterized along the three dimensions of colourfulness (hue, saturation and luminosity). Thus the total dimensionality of vision is 5. Audition oper6 ates along two dimensions (intensity, pitch ); olfaction, gustation and tactition are three or four7 dimensional. Furthermore, vision enables in a human being: i) The perception of the actual presence of an object (haecceitas). ii) The perception of the manifest nature of an object (quidditas). iii) The perception of change and movement. 1 2 3 4 5 6 7 Gen. 1:3. Gen. 1:1, 1:2. E.g. in the cosmogonies of the Ancient Greeks and of the Aztecs. Aristotle Soul: Β 7. Carnap LAdW: § 86. The perception of melody, harmony, and rhythm is mediated by the perception of the variation of pitch and intensity. Carnap LAdW: 121. 1 iv) The perception of the aesthetic value of a static (a painting or a sculpture) or a processual object (a dance, a theatre performance or a film). In contrast, audition enables only the perception of the aesthetic value of a process, e.g. the harmony of a melody. v) The perception of beauty in nature. 2. The Need for a Philosophy of Light Why has light this exceptional position in nature and in human life? Why is it so important that God created it separately before any other creature, uttering an explicit command? Why was the divine work completed only after the creation of light? In order to answer these questions and to understand the nature of light, a “Philosophy of Light” is needed that integrates all mentioned aspects in one coherent, consistent and explicative metaphysical theory. We find the first elements of such a philosophy in Thomas Aquinas’ Summa Theologica, namely in the 67th quaestio of the first part. Thomas explains there that light, although being a quality (qualitas) and not a sepa8 rate object like a star or the sun, was nevertheless created on the very first day of creation because it is the quality of the first body, namely of the world as a whole. In other words, Thomas claims that light is a fundamental property of the universe as a whole and that its extension is coincident with the extension of matter and space at any point of time that has passed since creation. Thomas distinguishes further between the primordial light that was created explicitly on the first day of creation, and the light that emanates from the sun and the stars that were created on the fourth day. The discrepancy that arises from the fact that the luminous bodies, which bear the quality of light, were created after the light itself as a quality, is explained by Thomas with the remark that the luminous bodies modify the primordial light and give to it a particular form, as sun9 light, moonlight and light of the stars. The Thomistic determination of the ontological status of light might have been adequate for the explanation of the light-related phenomena that were known at his time, however the further empirical investigation of its nature, especially in the wake of the Galilean and Newtonian reform of Physics, revealed that light also has properties in common with physical bodies, namely a finite 10 speed, “elasticity”, impulse, and that it can interact gravitationally with massive bodies. These new discoveries made the revision of the ontological status of light necessary, posing a dilemma to the philosophers: either to accept the mere “corporeal” character of light and to abandon its exceptional position in nature with the consequence to separate also the divine from the mundane truth, and in the long run to give up the idea that there is something like divine truth whatsoever; or, to try to secure this exceptional position in nature – and as a consequence to correlate divine and mundane truth – by accepting a special mode of existence for light that it does not share with any other natural entity. The first way has been followed by the various empiricist philosophers and will not concern us further in this essay, since it renders a specific “Philosophy of Light” pointless. Schelling and Hegel, however, who both try to integrate the reflection on the natural world in a greater philosophical system, so that matter and spirit become aspects of the same absolute reality, have walked the second way. For Schelling, light is the manifestation of the “first potency” of the absolute on the 11 spiritual side of the identity relation between spirit and matter. Schelling symbolizes this relation 8 9 10 11 In Thomas’ terminology, light has the nature of a quality and not of a body (Summa Ι, 67, 4). Summa I, 70,1. The discovery and the first determination of the speed of light are attributed to the Danish astronomer Ole Rømer. However, there is evidence that also the Italian-French astronomer Giovanni Domenico Cassini made similar measurements. Cf. Bobis and Lequeux 2008. Schelling Darstellung: § 60 ff. 2 with A = B, where A denotes the spiritual or rational aspect and B the material aspect of reality. Light is the manifestation of the first potency of A, namely A2, so that the identity relation now becomes A2 = (A = B). This formula makes understandable that the material phenomenology of light relies on its nature of being A2 and not on an internal structure in B. This has the consequence that Schelling does not see any contradiction between a corpuscular and a wave character of light in the natural world, but claims that both characters together make up the material aspect 12 of light. Schelling’s concept of light underlines its exceptional position in nature. However, the structure of the system of Schelling’s metaphysics has a very strong intuitive and stipulative character that makes the whole system quite opaque and difficult to understand. Schelling himself claims that his 13 system is organized along a Spinozist logical line of argumentation, but he does not seem to realize that the material terms, which he regards as inevitable elements of the philosophy of nature, as well as the whole system of “potencies” cannot be deduced in a mere formal manner, a problem Spinoza was aware of so that he therefore constructed his system not only along a set of axioms, but also on the basis of some primordial material definitions. This deficiency in the conceptual structure of Schelling’s system is avoided in Hegel’s system, which consists of three parts: logic, philosophy of nature and philosophy of spirit. In the first part, logic, Hegel outlines both the material and the formal principles of the process of the manifesta14 tion of the Idea in the subsequent three phases, nature, subjective spirit and objective spirit, which are explicated in his philosophy of nature and the philosophy of spirit. In the first phase of this process that makes up the philosophy of nature, Hegel also follows the biblical narration – and in fact also the Thomistic interpretation. Light is, according to Hegel, the first moment of identity of the Idea with itself, manifesting itself in three modes: as an abstract substance, the light proper, as an individual self-luminous body, the star, and as the totality of 15 both, the Sun. 3. Man, God, and Light Despite its explicitness compared with the determination of the nature of light in Schelling’s system, Hegel’s determination of this nature does not explain, however, why light is ontologically necessary for the “evolution” of the world through the various steps of nature and spirit towards its perfection in the absolute spirit. I think that this necessity becomes intelligible only if we accept the biblical concept of man as image of God as the underlying principle of both nature and spirit in Hegel’s philosophy, and as a hermeneutical guideline for the understanding of it. This concept can be translated in Hegelian terms as the relation between the conditional, or relative spirit that manifests itself as man and the unconditional, or absolute, spirit that Hegel regards as the ade16 quate philosophical description of the essence of the biblical God. 12 13 14 15 16 Schelling Weltseele: 37-38. Schelling Darstellung: Vorerinnerung, p. 9. For Hegel, the Idea of the world represents the concept, or the plan, of the universe, the realization of which culminates in the absolute spirit. (“[T]he Idea as such is nothing but the Concept, the real existence of the Concept, and the unity of the two“, Hegel Aesth.: 106). Hegel PN: § 275. I use the contrast pairs conditional/unconditional or relative/absolute instead of the pair finite/infinite for describing the contrast between human and divine spirit, because human spirit is also infinite in its capability for perfection, albeit this capability is mainly potential and not actual. Thus, human spirit exerts its intellectual powers only conditionally, i.e. in dependence both from the manifestations of the absolute spirit and in dependence on the particular historical and material circumstances. 3 The necessity of light as an intermediate substance that enables the manifestation of this relation results from the fact that the image relation between man and God is, by its very nature, a mediated relation. If it were not mediated, then man would be either, a) a mere mode of God in the sense of Spinoza, or b) a monadic appendix, or a monadic emanation, of God in the sense of Leibniz. The further consequence of man being an immediate emanation of God in the sense of Leibniz would be that nature in its totality would be either an emanation of man’s existence, or, as John 17 McTaggart argues, an unreality. On the other hand, if we would accept the Spinozist solution, then nature becomes another mode of God that is completely independent from the existence of man. This conception would, however, render the factual interdependence of Man and nature unintelligible. The image relation between man and God is then mediated. In order to be this, the mediating instance must be at least in one aspect similar to the nature of the image, i.e. of man. This means that the image must be “embedded” in the mediating instance. If this were not the case, then the mediating instance would be either redundant, or unintelligible both for the absolute original 18 (God) and its conditional image (man); it would be a “second” God. The mediating instance is then itself a manifestation or emanation of the absolute, i.e. God’s creation. As a separate creation this instance has its own nature, which is, however, in contrast to the nature of the image not oriented towards the absolute. This mediating instance is nature, the natural world. In Hegel’s 19 words “nature has yielded itself as the Idea in the form of otherness”, i.e. it is the manifestation of the Idea that is not by itself. The existence of man as image of God is realized as embedded in nature, which is the instance that mediates between man and God and enables the manifestation of the image relation between them. This complex relation between God, man and nature can be analogized to the relation between a mirror, a person and the reflection of this person in the mirror. The reflection is embedded in the mirror. Its “material” is the same as the material of the mirror. However, its form is the same as the person who is reflected in the mirror. Thus the person, the original, determines the quiddity of the reflection. The reflection has, with regard to the person, a conditional existence, while the person exists, relative to their reflection in the mirror, unconditionally. In order, however, for the image to become visible, i.e. actual, it must be separated from its “environment” in the mirror. As long as this does not happen, the image exists only potentially. This separation cannot be performed as long as the original, the image, and the mirror remain in darkness; its manifestation requires the emergence of light. The analogy between person, mirror, image, and light ends here since in reality the light is also part of nature; it belongs to the material aspect of nature. However, in order for light to be able to separate man – as God’s image –, from the rest of nature – as the mediating instance between God and man –, it must possess a certain degree of autonomy and self-reference with regard to the rest of nature. Therefore, light is in Hegelian terms the first manifestation of the Idea-by-itself; however, in contrast to spirit not for-itself, but for-other. For this reason, light cannot and must not refer to itself, as a self-conscious entity would do, but it exists as manifest becoming, as being in movement, as becoming that becomes. 17 18 19 McTaggart 1927: §§ 303 ff. This problem is first addressed in the platonic Timaios. Hegel PN: § 247. 4 4. Light, Space, and Time 20 As actual movement, light also realizes the media of movement, namely space and time: 21 a) Light creates space and time. b) Light propagates itself in space, and needs only space for its propagation. c) Light is an effective cause. As such, light can have effective aspects that are not directly vis22 ible, and it can be used for transmitting information. d) Light specifies the measure of movement, i.e. a constant limiting velocity. The constancy of the speed of light results in the uniform flow of time in the space that is created by this 23 movement (homogeneity of time). From d) two corollaries follow: i) ii) Simultaneity exists only within the space created by a single “light sphere”, i.e. within a single inertial system. Synchronicity can be established only when the light spheres of two inertial systems meet each other. The class of time-measuring devices (clocks) is not homogeneous. This means that the phase equality relation between clocks is not necessarily transitive. Light marks thus the cosmogonical and the methodical beginning of the world. The first light (created in the biblical narration by the divine command “fiat lux!”, or at the “Big Bang” of the modern secular cosmogonical narration), created space-time, in which nature, the known world, is established. It is the world that contains sources of light – the stars – and bodies that reflect light. It is the world of day and night, the world of sunshine and cloudiness, the world of full moon and of the nocturnal sky, where the myriads of the diamond of the Milky Way shine. It is the world where the variety of life unfolds and its daily drama takes place. This world, this nature, being the mediating agent between God and man is constituted in such a way that it provides accommodation for man and its needs. Therefore: a) Nature is the manifestation of the Idea in the form of otherness. b) Nature is the manifestation of the Idea as something, i.e. as quiddity. c) Nature is designed in such a way that is in principle “man friendly”, i.e. nature supports Man’s existence and Man has not to fight against a hostile environment to secure his existence. This does not mean that Man’s existence is granted and that Man is not forced to sustain his existence actively, but this activity is not rendered futile by Nature. Even if we accept the emergence of man as the result of a natural evolution, this evolution has taken place in nature and not outside of it. 5. Cosmos: The Perfection of Nature by the Light of Spirit Nature is the manifestation of the Idea. It has therefore also an aspect of perfection, i.e. nature is – at least potentially – the manifestation of beauty, because “the beautiful is characterized as the 24 pure appearance of the Idea to sense”. The notion of the perfect nature, i.e. of nature perceived 20 21 22 23 24 For a detailed account of the medial nature of space and time cf. Psarros 2016. Hegel PN: § 275, Addition. This aspect of light is referred to as “electromagnetic radiation”. The question of whether electromagnetic radiation is a genus, as species of which is visible light, or if the properties and capabilities attributed to electromagnetic radiation are mere abstractions from its concrete nature, is a topic for a separate discussion. Therefore, Einstein’s relativistic reform of Newtonian physics is not owed to novel empirical information about the nature of light, but it is rather based on ontological considerations resulting from the nature of light as an effective agent. Hegel Aesth.: 111. 5 25 under the aspect of the manifestation of the ideality of the beauty, is the cosmos. For this perfection to become actual, the second manifestation of the Idea by itself is necessary – the spirit. Light renders this cosmos visible and paves the path to the manifestation of the conditional spirit in it, of man, of God’s image. With man’s appearance in the natural world begins the process of its penetration by reason. With reason, man perceives not only the haecceity, but he comprehends also the quiddity of things and recognizes their nature. In order to do this, man has to apprehend things by the senses – and the first sense is vision. Spirit can fulfil the task of comprehending the nature of things only if a “second light” elucidates them, the light of reason. This process is the forming and the final cause of man. It is therefore logically consequent that God commanded Adam and Eve: “Be fruitful and increase in number; fill 26 the earth and subdue it“. However, the first light, the physical light, captures the human mind in the present, in the specious appearance of things and dims the awareness of their nature. This becomes transparent to the light of reason only when the physical light is not present – at night. In the unpolluted by street and car lights darkness of the night, the universe is presented to us in its full majesty. Furthermore “[t]he owl of Minerva, takes its flight only when the shades of night are 27 gathering“ , and it is only consequent that Plato in the Laws appoints a “nocturnal council” with the task of deliberating the important things of the polis, the long-term planning, and the interpre28 tation of the constitution and the laws. Light is the identity of the Idea with itself, as physical light in the form of otherness, as spiritual light in the form of selfness or reflection. In the hypostasis of the physical, light renders the world a sensible reality and in its second hypostasis, as reason, or spirit, it renders the world intelligible, bridging the separation between natural things and their ideas. Further, because beauty is the shining of the idea in the world, physical light also reveals the aesthetic dimension of nature – natural beauty – and this revelation is not only presented to the conditional spirit, to man, but also 29 to the unconditional and absolute spirit, to God: “And God saw the light that it was beautiful“. 6. References Aristotle, Soul: Ἀριστοτέλης, Περὶ ψυχῆς, Athens 1997. Bobis and Lequeux 2008: Laurence Bobis, James Lequeux, Cassini, Rømer and the Velocity of Light, Journal of Astronomical History and Heritage, 11(2): 97-105 (2008). Carnap LAdW: Rudolf Carnap, Der logische Aufbau der Welt, Frankfurt, Berlin, Wien 1974 (reprint 1979). Gen.: Genesis, 21st Century King James Version. Hegel Aesth.: G.W.F. Hegel, Aesthetics – Lectures on Fine Art, transl. by T.M. Knox, Oxford 1975 (reprint 1988). Hegel PN: G.W.F. Hegel, Philosophy of Nature, transl. by M.J. Petry, London & New York 1970. Hegel PR: G.W.F. Hegel, Philosophy of Right, transl. by T.M. Knox, Oxford 1952. 25 26 27 28 29 “The beautiful is the Idea as the immediate unity of the Concept with its reality, the Idea, however, only in so far as this its unity is present immediately in sensuous and real appearance. “ (Hegel Aesth.: 116). Gen. 1:28. Hegel PR: Introduction. Plato Nomoi: 961b6-961b8. Gen. 1, 4. I translate here the Greek word καλόν as beautiful because this is the main meaning of this word. Compare: καλός κ’ἀγαθός – beautiful and good/virtuous. 6 McTaggart 1927: John McTaggart Ellis McTaggart, The Nature of Existence, Cambridge 1927 (reprinted 1968). Pedersen 2008: Kurt Møller Pedersen, Leonhard Euler's Wave Theory of Light, Perspectives on Science 16: 392-416 (2008). Plato Nomoi: Πλάτων, Νόμοι, Athens 1992. Psarros 2016: Nikos Psarros, The Ontology of Time – A Phenomenological Approach, in: Stamatios Gerogiorgakis (ed.), Time and Tense – Unifying the old and the New, Munich 2016, pp. 383428. Schelling Darstellung: F.W.J. Schelling, Darstellung meines Systems der Philosophie, in: Schriften von 1801-1804, Darmstadt 1988. Schelling Weltseele: F.W.J. Schelling, Von der Weltseele – Eine Hypothese von der höheren Physik zur Erklärung des allgemeinen Organismus, Berlin 2016. Summa: Thomas Aquinas, Summa Theologica, complete English edition in five volumes, translated by Fathers of the English Dominican Province, Westminster, Maryland 1981 (reprint of the 1911 edition). 7
