OverviewConsciousness In Modern Philosophy
Since its inception in the seventeenth century, the history of the modern idea of consciousness is intertwined with the history of the idea of science and the scientific worldview. Consciousness has been on the rims of the scientific worldview, at once a challenge to the applicability of the scientific method for understanding consciousness, and an alternative possible source of knowledge, more certain than scientific empirical knowledge that must rely on the senses.
The Cartesian revolution.
When Descartes initiated the discussion of consciousness in Europe, it was against the backdrop of the scientific revolution of the seventeenth century. Science presented then a materialist and mechanistic worldview. Pre-Newtonian science considered the universe to be composed of material particles that generate motion and change by direct physical interaction and transmission of force, much like clockwork or a billiard game. Descartes proposed to distinguish humans from artificial or organic machines (brutes) by the presence of mind, language, reason, and consciousness. Descartes believed that consciousness provides an intimate and certain source of knowledge, superior to empirical knowledge that is founded on the fallible and often misleading evidence of the senses. What we take as our sensory input may be a dream; we may be "brains in a vat," as later epistemologists put it. But conscious introspection can provide sure knowledge about ourselves that is independent of the senses. For example, Descartes's famous saying, cogito ergo sum, "I think, therefore I am," suggests that any act of thinking implies the presence of a thinker, a person, and therefore self-knowledge of personal existence is certain. Descartes then divided the universe into material things, res extensa, that exist in space, and res cogitas, consciousness, a mind that thinks but has no material extension. The resulting duality of mind and body came to be known as dualism. Dualists must explain how mind and body interact in the person despite their qualitative differences, and respond to attempts to reunify mind and body in monistic philosophic systems that consider everything to be either ideal, part of immaterial consciousness, or material, so that consciousness is part of the material world that science describes—brain states, for example.
The phenomenological tradition.
Immanuel Kant (1724–1804) revolutionized philosophy by distinguishing the introspective study of the structure of pure consciousness as the subject matter of philosophy, distinct from the study of nature, the subject matter of science. Kant studied how any sensory input must appear in consciousness, in what he called the categories such as time, space, and causal order. However, Kant also concluded that while philosophical introspection may offer an infallible knowledge of the structure of consciousness, there could never be knowledge of the world as it is independent of consciousness.
Georg Wilhelm Friedrich Hegel (1770–1831) attempted to reunify consciousness with the world in an idealist monistic scheme according to which the world is a spirit, and our consciousness is that part of the world that can achieve self-consciousness. Consciousness, then, is what determines being, what happens to exist materially at any moment.
In his 1874 Psychology from an Empirical Standpoint, Franz Brentano (1838–1917) introduced the thesis that all conscious states are intentional. We experience the world against the background of our intentions, manifested in a sense of meaningfulness or meaninglessness. For example, my current conscious state includes my thoughts about this entry, vision of a computer screen, the sounds of a Mahler symphony in the background, and so forth. All these experiences are imbued with meaning against my intentions, to write a comprehensive and informative entry, to enjoy listening to my favorite composer, and so on. Had my intentions been different, say to earn a lot of money and to become better acquainted with contemporary rap, my state of consciousness, though including the same sights and sounds, would have been different and the experience much less meaningful.
Brentano taught at the University of Vienna. Among his most remarkable students were both Edmund Husserl (1859–1938) and Sigmund Freud (1856–1939). The first founded the philosophical school of phenomenology, the culmination of the tradition that considered consciousness to be the subject matter of philosophy and direct introspection the sure method. The second extended intentionality to unconscious states, but also shifted the focus of intellectual discourse from consciousness to the unconscious.
Husserl's phenomenology is the last great school of philosophy to attempt to found certain knowledge on introspection of our consciousness. Husserl thought that with the scientific revolution, people lost awareness of pristine and immediate consciousness, which has been emptied of meaning because they objectify, abstract, and conceptualize. Husserl sought to recapture and philosophically analyze this immediate consciousness. Husserl called his method epoché, the suspension of belief in the distinction between subjective and objective phenomena that allows immediate consciousness to "appear." Within epoché, consciousness appears full of meaning, prior to conceptualization, and so the philosopher who follows Husserl's method will be able to analyze the universal aspects of consciousness. Husserl called what should appear to anybody who goes through epoché the "life-world." Husserl's description of the life-world he discovered may be interpreted as a reaction against increasing modernity, urbanization, and loss of traditions and security in Europe in the early twentieth century; against the loss of a pristine bucolic world of farmers rooted in their land; and against the growing gap between the scientific worldview of matter and energy, galaxies and atoms, and the human perspective on the world of earth and sky, flowers and friends. Husserl's method of epoché proved susceptible to personal biases and so generated accounts as different from each other as those of Martin Heidegger and Emmanuel Levinas (1906–1995). Husserl was also criticized for not considering possible differences between human consciousness in different historical eras or cultures, though such philosophical anthropology has never been his purpose.
The gap between the modern scientific worldview and human point of view also spurred the explorations of the French philosopher Henri-Louis Bergson (1859–1941). Bergson was particularly interested in our consciousness of time. Physics (except for Newton's law of entropy, which stipulates increasing disorder in the universe in the direction of time) is indifferent to the direction of time from past to future. Einsteinian relativity considers time as a dimension that can be stretched or compressed in relation to gravity and velocity. Our conscious experience of time is quite different. Bergson attempted to distinguish our conscious experience of time as a continuous duration from its scientific divisibility into moments.
At the same time, "stream of consciousness" novelists such as Henry James, Arthur Schnitzler, Virginia Woolf, and especially James Joyce in Ulysses explored consciousness and time through a narrative method that attempted to record everything that goes through their protagonist's minds.
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