firmly in place within me,but it was about this time that I became aware of another language that would change my life.This was the language of mathematics,and I fell in love with it for two reasons.One was its inherent beauty-a beauty that stemmed from its economy and lack of ambiguity -the very tight association between symbol and meaning,the knife-edged clarity of each statement,the leanness of its form.The other reason I became enchanted with the language of mathematics was because of what you could do with it-how you could use it to make sense of our physical universe.I devoured books on classical physics with the same emotional energy as I consumed poetry and fiction,and to this day I maintain that science and art are fuelled by the same fire-that passionate urge to understand.There is a beautiful line in a picturebook called The Sea of Tranquility by Mark Haddon (whom many of you will know as the author of The Curious Incident of the Dog in the Nighttime)-which is about a young boy obsessed with the moonlanding,and is set appropriately in 1969. The line is this:He got an atlas of the moon for Christmas and he read it like a storybook',and it never fails to bring tears to my eyes.Because the atlas of the moon is a storybook to those who are passionate about the landscape of the moon,and Maxwell's equations are to me as poetry,and did haunt me once as deeply as a good poem.I am often asked whether I feel divided between my scientific persona and literary persona,and the answer is a resolute 'no',and I think I have just explained why.Science and writing are indeed different adventures,but behind them both is the same need-the need to comprehend a little further,a little better the world within us as well as the world without. 9 So where do they differ then?In language,of course.Which brings me to my second point-language affects not just experience,but also comprehension.In the case of science,this comprehension is advanced by the lack of ambiguity-whereas in literature,it is often ambiguity itself that enriches our understanding of the human condition.I fear I have witnessed a drive towards the opposite in the last few decades -with literature or at least what passes for modern fiction,being judged increasingly in terms of its clarity and accessibility',and certain types of ambiguity being tolerated within science-both,for me,symptomatic of a laziness with which society seems to be afflicted at the present time.I will give you examples of both. 10 First,science.Here,I shall restrict myself to my own specialized field,because as Peter Doherty mentioned in his excellent lecture on Tuesday which some of you may have attended-we are all novices in every field but our own.My love affair with mathematics never ended,and eventually I found myself engaged in the rather peculiar act of using mathematics to understand infectious disease.This is for me a very rewarding business(and also pays the mortgage and the school fees)particularly as it combines my interests in biology and mathematics.So how do you use mathematics to gain insight into infectious disease? 11 So I use mathematics to generate testable hypotheses about infectious disease systems,and consider it to be an indispensable tool in the both guiding experimentsfirmly in place within me, but it was about this time that I became aware of another language that would change my life. This was the language of mathematics, and I fell in love with it for two reasons. One was its inherent beauty – a beauty that stemmed from its economy and lack of ambiguity – the very tight association between symbol and meaning, the knife-edged clarity of each statement, the leanness of its form. The other reason I became enchanted with the language of mathematics was because of what you could do with it – how you could use it to make sense of our physical universe. I devoured books on classical physics with the same emotional energy as I consumed poetry and fiction, and to this day I maintain that science and art are fuelled by the same fire – that passionate urge to understand. There is a beautiful line in a picturebook called The Sea of Tranquility by Mark Haddon (whom many of you will know as the author of The Curious Incident of the Dog in the Nighttime) – which is about a young boy obsessed with the moonlanding, and is set appropriately in 1969. The line is this: ‘He got an atlas of the moon for Christmas and he read it like a storybook’, and it never fails to bring tears to my eyes. Because the atlas of the moon is a storybook to those who are passionate about the landscape of the moon, and Maxwell’s equations are to me as poetry, and did haunt me once as deeply as a good poem. I am often asked whether I feel divided between my scientific persona and literary persona, and the answer is a resolute ‘no’, and I think I have just explained why. Science and writing are indeed different adventures, but behind them both is the same need – the need to comprehend a little further, a little better the world within us as well as the world without. 9 So where do they differ then? In language, of course. Which brings me to my second point – language affects not just experience, but also comprehension. In the case of science, this comprehension is advanced by the lack of ambiguity – whereas in literature, it is often ambiguity itself that enriches our understanding of the human condition. I fear I have witnessed a drive towards the opposite in the last few decades – with literature or at least what passes for modern fiction, being judged increasingly in terms of its clarity and ‘accessibility’, and certain types of ambiguity being tolerated within science – both, for me, symptomatic of a laziness with which society seems to be afflicted at the present time. I will give you examples of both. 10 First, science. Here, I shall restrict myself to my own specialized field, because as Peter Doherty mentioned in his excellent lecture on Tuesday which some of you may have attended – we are all novices in every field but our own. My love affair with mathematics never ended, and eventually I found myself engaged in the rather peculiar act of using mathematics to understand infectious disease. This is for me a very rewarding business (and also pays the mortgage and the school fees) particularly as it combines my interests in biology and mathematics. So how do you use mathematics to gain insight into infectious disease? 11 So I use mathematics to generate testable hypotheses about infectious disease systems, and consider it to be an indispensable tool in the both guiding experiments