René Descartes and John Locke, a tale of two thinkers. As you will see, this dynamic duo made quite a splash in the waters of history and the ripples can still be seen today. Before I go any further I'm going to have to bore you with a couple of definitions which are rather important to our subject.

The terms apply to formal logic and represent two distinct methods of understanding the world. One is called deductive reasoning, the other inductive reasoning and both have been applied to the search for truth. In inductive reasoning, you start with a bunch of observed facts and then come up with some sort of general rule or principle which accounts for these facts.

Deductive reasoning works just the other way around. It assumes you already have some basic truths which you then use to arrive at valid conclusions. Deductive reasoning has the advantage that using the correct algorithm will guarantee the correct results providing that your original premises are correct to begin with.

With inductive reasoning there is always an element of doubt because to use an example, if you've observed 99 white swans it is still possible that not all swans are white. With deductive reasoning, on the other hand, if you begin with the wrong premise such as 'all swans are blue', your conclusions will also be wrong. There's a little more to it than that, but you get the idea.

René Descartes
Descartes is an enigma in some ways. Although he had a refreshing distaste for the voodoo logic of his day steeped as it was in the questionable science of the scholastic movement, when push came to shove he was equally capable of skewing his own thinking when confronted with the ingrained dogma of the church.

His philosophy and logic, called Cartesian was important because he substituted mechanical interpretations of physical phenomena for the vague spiritual concepts of previous thinkers. At the same time he ended up with elaborate and convoluted explanations of a number of physical phenomena which were just plain wrong.

For instance, although he had at first been inclined to accept the Copernican theory of the universe with its concept of a system of spinning planets revolving around the sun, he abandoned this theory when it was called a heresy by the Roman Catholic church. Instead he came up with a theory of vortices in space, whirling about the sun all bathed in an invisible "fluid" he called ether.

Also despite his mechanistic outlook, he accepted the traditional religious doctrine of the immortality of the soul maintaining that mind and body are two distinct substances. This fundamental separation of mind and body, known as dualism, raised the problem of explaining the way in which two such different substances as mind and body can affect each other, a problem that he was unable to solve and that has been a concern of philosophy ever since.

Cogito, ergo sum, "I think, therefore I am."
René Descartes was born 1596 in La Haye, Touraine, France the son of a minor nobleman. Educated by the Jesuits he followed the usual classical studies as well as receiving instruction in mathematics and in Scholastic philosophy. In 1616 he graduated with a law degree but never practiced law. Although he spent time in both Italy and his native France, he spent most of his adult life in Holland living in Amsterdam, Deventer, Utrecht, and Leiden to name a few. Most of his major works were written there.

Descartes is sometimes called the father of modern philosophy because he introduced the idea that things aren't necessarily true simply because someone or some group claims they are true. To pursue this idea he used the technique of ridding his mind of all preconceived notions and build a philosophic system from scratch.

As a starting point he doubted all things. Some critics suggest this created an unsolvable problem because if he doubted everything, he could not be sure after all, that the ultimate fact of his own existence is certain. Even his famous "Cogito, ergo sum" cannot be relied on either because it too has no real objective value.

He followed Francis Bacon and Galileo in criticizing traditional methods and beliefs, but unlike Bacon, who argued for an inductive method based on observed facts, he made mathematics the model for all science, applying its deductive and analytical methods to all fields. This was likely one of the points of issue with Pierre Gassendi. It was also one of the differences with John Locke.

John Locke
For those of us and I suspect that includes most of us, for whom history is all about dry facts and lifeless dates, people and statistics, John Locke may prove to be an interesting diversion. As any history textbook will tell you, Locke was born in the village of Wrington, Somerset, on August 29, 1632. He was educated at the University of Oxford and lectured on Greek, rhetoric, and moral philosophy at Oxford from 1661 to 1664. Oh yeah and he died on October 28, 1704.

See, that's the kind of gripping stuff that is guaranteed to induce sleep in even the most committed insomniac. So let's not go there. What makes Locke interesting is the fact that whether you realize it or not, many of the ideas that guide your thinking and that of the institutions that rule our lives began with him.

Locke believed that the mind of a person at birth was a tabula rasa, a blank slate upon which knowledge is imprinted through experience. He did not believe in intuition or theories of innate conceptions. As part of this he felt that all persons are born good, independent, and equal.

Sound familliar? It does to me. Think for a moment how these ideas influence education, the criminal justice system especially as it applies to rehabilitation, labor relations and also our attitudes to how we do our science. Think for a moment about how they influence you.

Locke was an avowed enemy of the "Devine Right Of Kings". He argued that sovereignty did not reside in the state but with the people, and that the state is supreme only if it is bound by a clearly stated set of guiding priciples or laws. You will not be too surprised to learn that his ideas had a great influence on the framers of the U.S. constitution as well as the way the new nation's institutions of government were constituted.

Those Reliable Sources
One of the problems that comes from having your thinking influenced by sources of which you are only dimly aware is the fact that they take on a halo of "self evident truths" and unassailable assumptions. This is not a problem when there is no problem but it becomes a problem when there is, get it?

A famous quote by John Maynard Keynes reads:

"The ideas of economists and political philosophers, both when they are right and when they are wrong, are more powerful than is commonly understood. Indeed, the world is ruled by little else. Practical men, who believe themselves to be quite exempt from any intellectual influences, are usually the slaves of some defunct economist. Madmen in authority, who hear voices in the air, are distilling their frenzy from some academic scribbler of a few years back."

Keynes was of course concerned with the "idiots" that ran the world of his day early in the twentieth century but things haven't really changed all that much. We are still influenced by certain philosophies and many of these can be traced to Rene Descartes and, more likely, to John Locke.

As is so often the case, Locke's approach to science was a reaction to the prevalent thinking of his day. This was a form of intellectual straight-jacket called Scholasticism, a system based mostly on the beliefs of Aristotle and the church. Locke's answer was a method of scientific study called empiricism.

Locke's empiricism emphasizes the importance of the experience of the senses in pursuit of knowledge rather than intuitive speculation or deduction. The empiricist doctrine was first suggested by the English philosopher and statesman Francis Bacon early in the 17th century, but Locke gave it systematic expression in his Essay Concerning Human Understanding (1690).

It is easy to understand Locke's passion for the empirical approach. In the 17th century, science was a mishmash of ideas inspired mostly by religious dogma, the ancient Greek wisdom of Aristotle and the rationalism of the likes of Rene Descartes. Much of it ran counter to any reality perceived by the senses.

The church both catholic and protestant was inclined to run roughshod over any theories that did not conform to traditional beliefs about creation. Protestants may have disagreed with their catholic brothers on some issues such as the proper route to salvation but when it came to science they pretty much agreed.

So What's The Problem?
Empiricism seems like an ideal antidote to these fusty ideas. Instead of the 'a priori' knowledge of the church, a scientific approach based on experiment and observation; instead of 'original sin', the innocence of a blank slate. Unfortunately, the real world doesn't really work like that either.

The first problem comes from the idea of the blank slate. The mind isn't, nor can it ever be totally blank. As pointed out by MIT professor Steven Pinker in his recent book 'The Blank Slate', there has to be some basic structure and content in the mind before you can start loading more stuff into it.

This is a vital point. For learning to happen, you must have a frame of reference to hang the new knowledge on. Without that it will simply "go in one ear and out the other". For instance, before you can relate to the color yellow you must have some idea about the concept of color to begin with. As Albert Eintein once said "It is the theory which determines what we can observe."

If, as Pinker suggests, much of the knowledge we posess wasn't so much poured in as it was "hard-wired" in before we were born, then we may have to rethink our notion of behavior. He's not advocating a return to "original sin" but he does cast some doubt on the effectiveness of reprogamming the mind to be a "good" person for example in someone who has devoted a lifetime to mayhem and crime.

Then there is the radical empiricist outright rejection of 'intuitive speculation'. How valid is that? As we have seen in other essays on this site, most breakthroughs in science are the result of what we can call the "eureka effect". You may recall Archimedes famous insight into displacement.

This is where we see the influence of Locke, when a lot of research still consists of endless sifting of data which may bring results but at what cost. There's a lot to be said for the alternative of exposing researchers to a stimulating environment that might act as an incubator for insights and breakthroughs.

We have touched on this topic elsewhere and we'll probably return to it from time to time. For now let's conclude by reflecting on the impact both Rene Descartes and John Locke had on our modern world. You will find it is substantial and keeping in mind that quote from Lord Keynes, we may be influenced more than we realize. If you know the source you can at least decide on its value.

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