Assistant Professor of Philosophy Alan Baker joined Swarthmore's faculty in 2003. Specializing in the philosophy of mathematics and the philosophy of science, his courses also include logic and philosophy of mind. Baker graduated with honors from Cambridge University and earned his Ph.D. at Princeton University. Write to him at abaker1@swarthmore.edu.

t might have been worth doing for the job title alone. I spent last July as 'philosopher in residence' at Whitehall, the 18th-century home of philosopher George Berkeley, located just outside Newport, Rhode Island. Berkeley is generally considered to be one of the "big three" British philosophers of the early modern period, along with John Locke and David Hume. He was already well-known in Europe when he embarked on a voyage to America in 1729; indeed he was said at the time to be the most famous European ever to visit the New World. Berkeley was hoping to found a progressive college on the island of Bermuda; the plan never came to fruition, but he spent three years living in Rhode Island, then an important center of colonial commerce and religious freedom. He bought a farmhouse and waited in vain for funding from the British crown to be approved.

The house, Whitehall, survived and is now owned and administered by the Colonial Dames of Rhode Island. As the headquarters of the International Berkeley Society, Whitehall boasts a comprehensive collection of early editions of Berkeley's works. These include a first edition of Alciphron, the book which Berkeley wrote during his stay in Rhode Island, inscribed "from the Author." Upstairs is a small research library with an impressive range of secondary literature on Berkeley, from the scholarly to the eccentric. (An example of the latter: Berkeley and the Paranormal.)

My duties were to live in the house, to raise the flag at dawn, lower it at dusk, to pursue my own scholarly research, and to give tours to any members of the public who managed to find their way there. Joining me in residence were my wife, Shelley, and 18-month-old daughter, Chloe.

It is an atmospheric place to stay. The property is bordered with dry-stone walls, and a garden of culinary and medicinal herbs faces one side of the house. Inside, the rooms are laid out as they might have been in Berkeley's time, with period furniture, books in English and in Latin, and 18th-century maps and portraits on the walls. Most of the house has no electric lighting so at night we lit candles which flickered in the cool evening breezes that blew in off the sea. A pendulum clock sitting on a bracket in the front parlor ticked noisily in the darkness.

If nobody is in Whitehall's front parlor to hear the clock, does it make a sound?

And if nobody is in the front parlor to hear the clock, does it make a sound? George Berkeley is primarily known today (aside from having a university town in California named after him) for his metaphysical position known as "idealism" or "immaterialism." This is often paraphrased by reference to the proverbial tree falling in the forest. Though there is no evidence that Berkeley ever said this, the point of the tree example is to illustrate the idealist view that sounds exist only as perceptions in people's minds.

Whether you find this claim plausible or not, it is not an accurate reflection of Berkeley's version of idealism. On the one hand, Berkeley's position is more extreme. He does not think that it is merely secondary qualities such as colors, sounds, and tastes which exist only as perceptions. Material objects such as tables, chairs, and planets also exist only as bundles of perceptions in people's minds. So if the falling tree is not seen or heard by anyone, then not only is there no sound, there is no tree! On the other hand, Berkeley's position has less radical consequences than one might think. Doesn't it imply, for example, that the furniture around you blinks out of existence each time you close your eyes? For Berkeley, an Anglican theologian and later a Bishop, the answer is no. The reason why not is encapsulated in the following 19th-century limerick:

Unlike most of the previous philosophers in residence at Whitehall, I am not a scholar of Berkeley per se. Instead my connection to Berkeley is via the subject matter of my research in the philosophy of science and the philosophy of mathematics. Specifically, I am interested in the link between methodology and ontology - in other words, that the way we evaluate different theories relates to what we end up believing exists.

For example, other things being equal we tend to prefer simpler theories over more complex alternatives. How simple is Berkeley's idealism? In one sense, it is simpler than the main alternative metaphysical view of the time, the dualism of Descartes. According to Descartes the world contains both material stuff (tables, chairs, human bodies) and mental stuff (human minds). According to Berkeley, the world contains only mental stuff. So idealism is simpler.

George Berkeley's theory of immaterialism is perhaps best summarized as, "Esse est percipi," to be is to be perceived.

Or is it? The number of things (or kinds of things) a theory commits us to is not the only measure of its simplicity. We also value theories which can condense a diverse array of phenomena into a few elegant principles. (A paradigm example: Newton's Three Laws of Motion.) Here the believer in material objects seems to have an edge over the idealist. She can explain, for example, the motion of a ball thrown through the air, by reference to the mechanical principles governing physical bodies. It is unclear whether the idealist has any corresponding explanatory principles at his disposal, since for him the ball is merely a succession of sense impressions. [For a more in-depth discussion of simplicity, see my Stanford Encyclopedia of Philosophy entry on this topic.]

Since Whitehall lies well off the beaten track, and is little advertised, visitors are few and interesting. We averaged a group or two a day, ranging from a Professor of architecture, to three Episcopal ministers from Ohio, to 16 high school students from a summer philosophy program at Brown University. My wife, Shelley Costa,  is an 18th-century historian and native of Newport specializing in women's history (Berkeley's wife, Anne, was another fascinating resident of Whitehall) and in the history of mathematics, she was at least as qualified as I was to lead tours of the house, so we shared this duty. Indeed it was Berkeley's interest in mathematics which formed the link to my second main area of research, in the philosophy of mathematics.

In 1734, Berkeley published a pamphlet entitled The Analyst: or a Discourse addressed to an Infidel Mathematician. This has an important place in the history of mathematics. The 18th Century saw the rise of mathematized natural science as the new source of authority on the workings of the world, increasingly taking over this mantle from theology. The Analyst was written as an attack on a key part of the mathematical basis of the new sciences, namely the calculus that had been co-invented by Newton and Leibniz in the 17th Century. The calculus at that time relied on the notion of infinitely small quantities, or infinitesimals. At some points in a calculus proof you must divide by an infinitesimal, so to avoid absurdity it cannot be equal to zero. But then later in the same proof the infinitesimal is assumed to be equal to zero so that it can be ignored in the final result. Berkeley claims that this notion of infinitesimal is therefore contradictory - he refers to infinitesimals derisively as "the ghosts of departed quantities," hence the new mathematics is less intellectually secure than theology. One of my interests is the relation between philosophy of mathematics and mathematical practice. In this respect, The Analyst is a fascinating example of a major philosopher writing for an explicitly mathematical audience. Moreover, Berkeley's concerns were taken seriously by practicing mathematicians.

I found it a uniquely satisfying experience to spend several weeks living and doing philosophy in a place still so imbued with the spirit of a major figure of the Western philosophical canon. My future ambitions for philosophy-related summer jobs? Most large companies have mission statements, some even have corporate philosophies. So why not "corporate philosopher"? If there isn't such a job, it ought to be invented.