Peter Atkins is the author of almost 60 books, including Galileo’s Finger: The Ten Great Ideas of Science, Four Laws that Drive the Universe, and the world-renowned textbook Physical Chemistry. His latest book is On Being, which is a scientist’s exploration of the great questions of existence. In the below video, Atkins is in conversation about the book with Meet the Author’s David Freeman.
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Today on OUPblog we’re celebrating the 100th International Women’s Day with posts about inspirational women. In this post, Patricia Fara, author of Science: A Four Thousand Year History, writes about the 18th century mathematician and physicist Émilie du Châtelet.
Émilie du Châtelet, wrote Voltaire, ‘was a great man whose only fault was being a woman.’ Du Châtelet has paid the penalty for being a woman twice over. During her life, she was denied the educational opportunities and freedom that she craved. ‘Judge me for my own merits,’ she protested: ‘do not look upon me as a mere appendage to this great general or that renowned scholar’ – but since her death, she has been demoted to subsidiary status as Voltaire’s mistress and Isaac Newton’s translator.
Too often moulded into hackneyed stereotypes – the learned eccentric, the flamboyant lover, the devoted mother – du Châtelet deserves more realistic appraisals as a talented yet fallible woman trapped between overt discrimination and inner doubts about her worth. ‘I am in my own right a whole person,’ she insisted. I hope she would appreciate how I see her …
Émilie du Châtelet (1706-49) was tall and beautiful. Many intellectual women would object to an account starting with their looks, but du Châtelet took great care with her appearance. She spent a fortune on clothes and jewellery, acquiring the money from her husband, a succession of lovers, and her own skills at the gambling table (being mathematically gifted can bring unexpected rewards.) She brought the same intensity to her scientific work, plunging her hands in ice-cold water to keep herself awake as she wrote through the night. This whole-hearted enthusiasm for every activity she undertook explains why I admire her so much. The major goal of life, she believed, was to be happy – and for her that meant indulging but also balancing her passions for food, sex and learning.
Born into a wealthy family, du Châtelet benefited from an enlightened father who left her free to browse in his library and hired tutors to give her lessons more appropriate for boys than for marriageable girls. By the time she was twelve, du Châtelet could speak six languages, but it was not until her late twenties that she started to immerse herself in mathematics and Newtonian philosophy. By then, she was married to an elderly army officer, had two surviving children, and was developing intimate friendships with several clever young men who helped her acquire the education she was not allowed to gain at university.
When Voltaire’s radical politics provoked a warrant for his arrest, she concealed him in her husband’s run-down estate at Cirey and returned to Paris to restore his reputation. Over the next year, she oscillated between rural seclusion with Voltaire and partying in Paris, but after some prompting, she eventually made her choice and stuck to it. For fifteen years, they lived together at Cirey, happily embroiled in a private world of intense intellectual endeavour laced with romance, living in separate apartments linked by a secret passage and visited from time to time by her accommodating husband.
For decades, French scholars had been reluctant to abandon the ideas of their own national hero, René Descartes, and instead adopt those of his English rival, Newton. They are said to have been converted by a small book that appeared in 1738: Elements of Newtonian Philosophy. The only name on the title-page is Voltaire’s, but it is clear that this was a collaborative venture in which du Châtelet played a major role: as Voltaire to
Today we’d like to introduce our latest regular OUPblog column: SciWhys. Every month OUP editor and author Jonathan Crowe will be answering your science questions. Got a burning question about science that you’d like answered? Just email it to us, and Jonathan will answer what he can. Kicking us off: What is DNA and what does it do?
By Jonathan Crowe
We’ve all heard of DNA, and probably know that it’s ‘something to do with our genes’. But what actually is DNA, and what does it do? At the level of chemistry, DNA – or deoxyribonucleic acid, to give it its full name – is a collection of carbon, hydrogen, oxygen, nitrogen and phosphorus atoms, joined together to form a large molecule. There is nothing that special about the atoms found in a molecule of DNA: they are no different from the atoms found in the thousands of other molecules from which the human body is made. What makes DNA special, though, is its biological role: DNA stores information – specifically, the information needed by a living organism to direct its correct growth and function.
But how does DNA, simply a collection of just a few different types of atom, actually store information? To answer this question, we need to consider the structure of DNA in a little more detail. DNA is like a long, thin chain – a chain that is constructed from a series of building blocks joined end-to-end. (In fact, a molecule of DNA features two chains, which line up side-by-side. But we only need to focus on one of these chains to be able to understand how DNA stores its information.)
There are only four different building blocks; these are represented by the letters A, C, G and T. (Each building block has three component parts; one of these parts is made up of one of four molecules: adenine, cytosine, guanine or thymine. It is these names that give rise to letters used to represent the four complete building blocks themselves.) A single DNA molecule is composed of a mixture of these four building blocks, joined together one by one to form a long chain – and it is the order in which the four building blocks are joined together along the DNA chain that lies at the heart of DNA’s information-storing capability.
The order in which the four building blocks appear along a DNA molecule determines what we call its ‘sequence’; this sequence is represented using the single-letter shorthand mentioned above. If we imagine that we had a very small DNA molecule that is composed of just eight building blocks, and these blocks were joined together in the order cytosine-adenine-cytosine-guanine-guanine-thymine-adenine-cytosine, the sequence of this DNA molecule would be CACGGTAC.
The biological information stored in a DNA molecule depends upon the order of its building blocks – that is, its sequence. If a DNA sequence changes, so too does the information it contains. On reflection, this concept – that the order in which a selection of items appears in a linear sequence affects the information stored in that sequence – may not be as alien to us as it might first seem. Indeed, it is the concept on which written communication is based: each sentence in this blog post is composed of a selection of items – the letters of the alphabet – appearing in different sequences. These different sequences of letters spell out different words, which convey different information to the reader.
And so it is with the sequence of DNA: as the sequence of the four building blocks of DNA varies, so too does the information being conveyed. (You may well be asking how the information stored in DNA is actually interpreted – how it actually determines how an organism develops and functions – but that’s a topic for a different blog post.)
You may be wondering how on earth ju
By Jim Baggott
If a tree falls in the forest, and there’s nobody around to hear, does it make a sound?
For centuries philosophers have been teasing our intellects with such questions. Of course, the answer depends on how we choose to interpret the use of the word ‘sound’. If by sound we mean compressions and rarefactions in the air which result from the physical disturbances caused by the falling tree and which propagate through the air with audio frequencies, then we might not hesitate to answer in the affirmative.
Here the word ‘sound’ is used to describe a physical phenomenon – the wave disturbance. But sound is also a human experience, the result of physical signals delivered by human sense organs which are synthesized in the mind as a form of perception.
Now, to a large extent, we can interpret the actions of human sense organs in much the same way we interpret mechanical measuring devices. The human auditory apparatus simply translates one set of physical phenomena into another, leading eventually to stimulation of those parts of the brain cortex responsible for the perception of sound. It is here that the distinction comes. Everything to this point is explicable in terms of physics and chemistry, but the process by which we turn electrical signals in the brain into human perception and experience in the mind remains, at present, unfathomable.
Philosophers have long argued that sound, colour, taste, smell and touch are all secondary qualities which exist only in our minds. We have no basis for our common-sense assumption that these secondary qualities reflect or represent reality as it really is. So, if we interpret the word ‘sound’ to mean a human experience rather than a physical phenomenon, then when there is nobody around there is a sense in which the falling tree makes no sound at all.
This business about the distinction between ‘things-in-themselves’ and ‘things-as-they-appear’ has troubled philosophers for as long as the subject has existed, but what does it have to do with modern physics, specifically the story of quantum theory? In fact, such questions have dogged the theory almost from the moment of its inception in the 1920s. Ever since it was discovered that atomic and sub-atomic particles exhibit both localised, particle-like properties and delocalised, wave-like properties physicists have become ravelled in a debate about what we can and can’t know about the ‘true’ nature of physical reality.
Albert Einstein once famously declared that God does not play dice. In essence, a quantum particle such as an electron may be described in terms of a delocalized ‘wavefunction’, with probabilities for appearing ‘here’ or ‘there’. When we look to see where the electron actually is, the wavefunction is said to ‘collapse’ instantaneously, and appears ‘here’ with a frequency consistent with the probability predicted by quantum theory. But there is no predicting precisely where an individual electron will be found. Chance is inherent in the collapse of the wavefunction, and it was this feature of quantum theory that got Einstein so upset. To make matters worse, if the collapse is instantaneous then this implies what Einstein called a ‘spooky action-at-a-distance’ which, he argued, appeared to violate a key postulate of his own special theory of relativity.
So what evidence do we have for this mysterious collapse of the wavefunction? Well, none actually. We postulate the collapse in an attempt to explain how a quantum system with many different possible outcomes before measurement transforms into a system with one and only one result after measurement. To Irish physicist John Bell this seemed to be at best a confidence-trick, at worst a fraud. ‘A theory founded in this way on arguments of manifestly approximate character,’ he wrote some years later, ‘howe
