Category Archives: Philosophy

Arts, Philosophy, Psychology, Science

Philosophy: David Hume

EMPIRICIST & ESSENTIAL THINKER (1711–1776)

– A narrative and critique on the philosophy of David Hume

David Hume is the philosophical hero of modern day sceptics and empiricists, renouncing all knowledge except that which can be gained from the senses. Alas, as Quine would later famously say, echoing Hume, what can be garnered from the senses is, after all, not much.

From Locke, Hume had drawn the conclusion that all human knowledge is based on relations amongst ideas, or “sense impressions”. Anything not given in experience is mere invention and must be ruthlessly discarded. As a result he denies the existence of God, the self, the objective existence of logical necessity, causation, and even the validity of inductive knowledge itself. His aim is twofold: at once demolitionary – to rid science of all falsehoods based on “invention rather than experience” – and constructive, to found a science of human nature. Much impressed with how Isaac Newton had described the physical world according to simple mechanical laws, Hume had a mind to do something similar for the nature of human understanding. His Treatise on Human Nature is a painstaking study in experimental psychology in search of general principles. In this, however, Hume can be seen as being spectacularly unsuccessful, primarily because his whole taxonomy of “impressions” and “ideas” is derived from the much discredited Cartesian model. Nevertheless, Hume’s negative program is a devastating example of the power of logical critique. His sceptical results, especially regarding induction, remain problematic for modern philosophers.

Hume observes that we never experience our own self, only the continuous chain of experiences themselves. This psychological fact leads Hume to the dubious metaphysical conclusion that the self is an illusion, and in fact personal identity is nothing but the continuous succession of perceptual experience. “I am,” Hume famously says, “nothing but a bundle of perceptions”. Following a similar line of thought, Hume notices that the force that compels one event to follow another, causation, is also never experienced in sense impressions. All that is given in experience is the regular succession of one kind of event being followed by another. But the supposition that the earlier event, the so-called “cause”, must be followed by the succeeding event, the “effect”, is merely human expectation projected onto reality. There is no justification for believing that there is any casual necessity in the ordering of events.

Hume’s scepticism does not stop there, and the belief in causation is just a special case of a more general psychological trait: inductive reasoning. Inductive reasoning is the process that leads us to make generalisations from observing a number of similar cases. For example, having observed many white swans but no black swans, one might seemingly be justifiably led to the conclusion that “All swans are white”. Equally, being aware that men often die, we conclude “All men are mortal”. But such generalisations go beyond what is given in experience and are not logically justified. After all, black swans were found in Australia, and there is always the logical possibility of coming across an immortal man. Hume claimed that inductive reasoning could not be relied upon to lead us to the truth, for observing a regularity does not rule out the possibility that next time something different will occur. Since all scientific laws are merely generalisations from inductive reasoning, this so-called “problem of induction” has been pressing for philosophers of science. Trying to show how induction is justified has taxed them throughout the 20th and 21st Centuries. Karl Popper is notable for offering the most promising solution to Humean scepticism. Popper’s brand of scientific method, ‘falsificationism’ gave rise to a whole new area of debate in the philosophy of science. According to Popper, the mark of a scientific theory is whether it makes predictions which could in principle serve to falsify it.

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Philosophy, Science

Philosophy and science

THE PERTINENCE OF PHILOSOPHY vs. SCIENCE

THROUGHOUT much of the history of philosophy, there was no such thing as science in its modern form: in fact, it was from philosophical enquiry that modern science has evolved. The questions that metaphysics set out to answer about the structure and substance of the universe prompted theories that later became the foundations of “natural philosophy”, the precursor of what we now call physics. The process of rational argument, meanwhile, underpins the “scientific method”.

Since the 18th century, many of the original questions of metaphysics have been answered by observation, experiment and measurement, and philosophy appeared to be redundant in these areas. Philosophers have since changed their focus to examine science itself. Some, like Hume, challenged the validity of inductive reasoning in science, while others sought to clarify the meaning of terms used by science, opening up a “philosophy of science” that considers areas such as scientific ethics and the way science makes progress.

ADVANCES IN SCIENCE

MOST of the sciences evolved from branches of philosophy, complementing them with scientific theories describing the physical world. But as the pace of progress accelerated with the scientific revolution of the Enlightenment, the natural sciences largely replaced metaphysics, and by the end of the 19th century psychology and neuroscience began to provide a scientific alternative to the philosophy of the mind.

In the 20th century, Albert Einstein’s theories seemed to provide a comprehensive explanation of the physical universe, but many aspects of the new physics threw up almost as many questions as answers – problems that science alone could not explain. And just as science appeared to be replacing aspects of philosophy, some philosophers turned their attention to science itself. Karl Popper proposed a practical answer to the problem of induction, the basis of scientific methods, while Paul Feyerabend questioned the notion of a single reliable scientific method, based on Thomas Kuhn’s idea that science makes advances not in a smooth progression, but in radical jumps.

. On the Origin of Species

The cultural influence of science reached a climax in the mid-19th century with the publication in 1859 of Darwin’s On the Origin of Species. Although it was a scientific rather than a philosophical work, his theory of evolution by natural selection put many aspects of philosophy in a new perspective. In the same way as Copernicus’s proposal of a heliocentric universe challenged religious authority and became symbolic of emergent Renaissance humanism, Darwin’s explanation of evolution presented humans as just another animal – part of the natural world rather than separate from it. In his later Descent of Man, he applied the principles of evolutionary theory specifically to humans, explicitly stating for the first time that we have evolved from animals, and so challenging previous notions of man as superior to other animals because of his ability to reason. But perhaps most important in terms of its effect on philosophy was the implicit idea that humans are not the pinnacle of God’s creation, but merely a stage in the evolution of the natural world.

ATOMIC THEORY

In the 5th century BCE, the philosopher Leucippus and his pupil Democritus proposed the revolutionary notion that everything is composed of indestructible particles in empty space. In other words, it was through philosophy that Atomic Theory first emerged.

Like many other philosophers, the Atomists, as they were later known, attempted to explain the reality of motion and change. Parmenides had said that these are mere illusions, since motion requires the existence of a void, which he deemed a logical impossibility.

Atomists turned this argument on its head, however, suggesting that since motion is patently possible, the void must exist, and matter must be free to move within it. Since the movement of matter takes place at a microscopic level, it is not visible. Matter is formed of minute particles that Leucippus called “atoms”, which exist in empty space, and the changes that can be observed in the cosmos are due to the motion of these atoms in the void. Each atom is an eternal and unchanging entity, both indestructible and indivisible, but capable of joining with others to form different substances and objects.

Where Parmenides posited eternal, immutable unity, the Atomists proposed an infinite diversity of eternal particles that gives rise to an ever-changing cosmos.

Building blocks

According to the Atomists, the atom is the basic unit of every material substance. These building blocks of matter are constantly in motion in the void, and react with each other, being either mutually repelled or attracted. There are countless kinds of atoms, which join together in different combinations to form the huge variety of substances. They then separate as those substances decay. The atoms themselves are immortal, and remain intact. They continue their movement throughout the void, continually and ceaselessly combining, separating, and reforming.

NEED TO KNOW

> The void described by the Atomists is more than empty space – it is an absolute absence of matter, akin to a vacuum.

> The word “atom” comes from the Greek atomon, meaning “uncuttable” or “indivisible”.

Kinds of Atom

Democritus suggested that atoms come in a range of sizes and shapes, their properties determining the characteristics of different substances. He proposed that the atoms of liquids are smooth and can move freely past one another, while solids have more rigid atoms that move less and can connect with other atoms.

AIR – Air atoms are light and wispy, and move freely and independently

WATER – The smooth, round atoms of water give it its flowing, liquid character

IRON – Atoms of iron have hooks that interlock to give the metal its solidity

SALT – The taste of salt is caused by its jagged atoms acting on the tongue

“Nothing exists except atoms and empty space; everything else is opinion.” – Democritus (5th century BCE)

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Arts, Philosophy

Philosophy: Plato’s allegory of the cave

UNDERSTANDING PLATO

Intro: In the Republic, Plato presented an allegory to show how our knowledge of reality is restricted by the deceptive information provided by our senses

A world of shadows

PLATO asks us to imagine a cave in which some prisoners are held captive. They are shackled to face the back wall of the cave and are unable to turn their heads. Their field of view is restricted to the wall in front of them, across which they can see images moving.

The captives are unaware that behind them, hidden by a low wall, another group of people are parading a variety of objects in front of a fire. It is the shadows of these objects that the prisoners can see in front of them. Because all the prisoners can see are the shadows, this is the only reality of which they are aware. They know nothing of the objects casting the shadows, and would not believe it if they were told about them. They are literally being kept in the dark about the true nature of the world that they inhabit.

The point that Plato is making is that our own perception of the world is similarly restricted, and that the things we believe to be real are merely “shadows” of the things that exist in the ideal realm of the Forms.

Platonic realms

At the heart of Plato’s philosophy is the notion that the world we live in is deceptive, and that our senses cannot be trusted. For Plato, our world is merely a shadow cast by a higher realm of the Forms.

A world of Forms

Plato, like many philosophers before and since, was an accomplished mathematician, and was fascinated by geometry. He observed that there are many instances of things that are, for example, circular in the world about us, and that we recognise them as instances of a circle. We can do this, he argued, because we have an idea in our minds of what a circle is – what he called the “Idea” or “Form” of a circle – and unlike the particular instances of circular things, this Form is an ideal circle, with no imperfections. Indeed, everything we experience – from horses to acts of justice – are particular things that we recognise by comparing them with their relative Forms in our minds.

What is more, Plato claimed that since we cannot perceive these Forms, they must exist in a realm beyond our senses – one that we recognise with our psyche, or intellect. This process of recognition is largely instinctual, but Plato argued that philosophers are needed to comprehend certain Forms. In Plato’s dualistic universe, the two world’s he describes are perceived in different ways. The earthly realm is experienced by our bodily senses; the ideal realm being understood by the mind or intellect. This is what the concept of Dualism means. In practice, this is why philosophers should be used to organise society and advise on ethical matters, a key tenet that runs throughout Plato’s philosophy.

Innate Knowledge

Plato believed that our knowledge of the Forms is something we are born with, not something we acquire through experience. Rather, we use our reason to access the Forms, in whose realm we lived before we were born. For Plato, philosophers are like midwives: their role is to bring to light what we innately already know.

ONE WORLD ONLY

Plato’s most brilliant student, Aristotle, did not agree with his mentor’s theory of Forms. Instead, he proposed that we learn about the world through experience alone.

Empiricism

Aristotle could not accept the idea of a separate world of ideal Forms. Plato had argued that the Forms – the qualities of being circular, good, or just, for instance – exist in a separate realm. Aristotle believed that there is only one cosmos, which we learn about through our experience of it. Although he accepted that “universal” qualities (such as redness) exist, he did not believe that they do so in a separate dimension. Rather, he said, they exist in each particular instance in this world.

For example, the idea of a “circle” is general: we have in our minds an idea of what constitutes a perfect circle. He explains that this is not because we have innate knowledge of the perfect (Form of a) circle, but because we experience circular things, and then generalise about them, having seen what they have in common.

For Aristotle, we gather information about the world through our senses and make sense of it by using our intellect or reason. In this way we build up ideas, apply labels to them, and make distinctions. As a philosophical stance, this is known as “empiricism”, as opposed to Plato’s “rationalism”.

Essential and Accidental Properties

Aristotle argued that all things have two kinds of properties. An essential property is what makes a thing what it is. Its other properties are “accidental” properties.

. An apple’s accidental properties include its colour, shape, and weight. It is an apple whether it is green or red, round or oval, large or small

. The apple’s essential property is the substance that it is made from

. The essential property of a ball, however, is its shape; the substance it is made of is an accidental property

NEED TO KNOW

> Epistemology is the branch of philosophy concerned with knowledge and the way in which we acquire it.

> Inductive reasoning is the logical process of making a general rule from a number of particular instances.

> Empirical knowledge is knowledge that is acquired by observation or experience rather than through reasoning.

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