Philosophy from Socrates to Descartes. A Brief Classical Introduction
Philosopher Gareth Matthews reports 6-year-old Tim asking, “Papa, how can we be sure that everything is not a dream?” (Matthews 1980, p. 1). Tim’s question is about knowledge. We suppose we live in a world with things like cars, houses, trees, other people, and places, but can we be sure we really do? Perhaps it’s a dream. If we are dreaming, nothing we experience as real would be so. Tim’s question is archetypal in philosophy. Since ancient times, philosophers have pondered reality and how we can know it. But do we need to worry about it? Distinguishing reality from illusion is, for most, as unproblematic as discerning being awake from dreaming. If someone asks, “Am I dreaming?” we don’t take it literally but take it as indicating that they have difficulty believing something.
Why have philosophers been obsessed with questions of reality and illusion? They started in ancient times with inquiries into reality. They sought first principles for reality, describing its ultimate nature (also referred to as metaphysics). Today we have several sciences telling us about reality, such as biology, chemistry, and physics. The picture conveyed by them goes beyond what the naked eye sees.
As a child, my head spun when I learned everything was made of atoms—a strange, buzzing, hidden reality in motion behind the appearances of our everyday world. Getting behind appearances is a philosophical and scientific pursuit. In the end, the objective is to understand reality. Science got us behind appearances to understand the atom, DNA, and germs. Scientific theories, however, are typically preceded by philosophical reflection. For example, a version of atomic theory was formulated by the Greek philosopher Democritus (460-370 BC) and his followers, who viewed the universe as being composed of minute atoms.
Democritus’s mode of explanation was reductive; it reduced the world to atoms. This mode of explanation continues to be important. It is, for example, a reductive explanation to say that water (at a macro level) can be reduced to H2O (at a micro level). Using this reductive explanatory framework, we can explain why water is liquid at some temperatures and solid at others—by studying how the molecules
© Springer International Publishing AG 2017
A. Hedman, Consciousness from a Broad Perspective, Studies in Neuroscience, Consciousness and Spirituality 6, DOI 10.1007/978-3-319-52975-2_2
interact.1 Reductive explanations are key to explaining physical reality. On the whole, modern science is often said to be reductionist, and the philosophy behind it is called reductionism.
There is something intriguing about reducing phenomena at higher levels to lower levels. Where does it stop? Does it stop with the subatomic quantum mechanical world beneath atoms? Here our classical concepts—our ways of thinking about the world at the macro level—cannot be readily applied. Contemplate the photon wave-particle duality. According to one way of measuring photons, they behave as waves; according to another, they behave as particles. Are they waves or particles; are they both? No answer seems entirely right, because classical concepts fail. In our everyday, classical world, something cannot be a wave or a particle depending on how we measure it. The quantum world stretches beyond full human understanding.
String theorists are developing abstract theories that may not be empirically verifiable. According to string theory, reality is vibrating strings to be understood mathematically. Some string theorists credit philosopher and mathematician Pythagoras (570-495 BC) for having initially proposed that reality is a mathematical harmony of vibrating strings.
Democritus and Pythagoras belonged to the pre-Socratic era of philosophy, commencing around 600 BC. The era is referred to as pre-Socratic, given the subsequent influence of the philosopher Socrates (470-399 BC) and his student Plato (427-347 BC) on the Western intellectual tradition. Philosophy reached such a mature state with Socrates and Plato that some see the history of Western philosophy as footnotes to their work. 
-  At least roughly, scientists are still discussing the details of why water behaves the way it does.
-  As mathematician and philosopher Alfred North Whitehead put it, “The safest general characterization of the European philosophical tradition is that it consists of a series of footnotes to Plato.”(Whitehead 1979, p. 39).