$19.4 THE IMPORTANCE OF BEING HUMBLE 673 understand the nature of air,the great physicist-philosopher Reaumur used the then common metaphor of a sponge-which,as Bachelard shows,goes back at least to Descartes.Why not?Many good physics teachers occasionally resort to such gimmicks to capture students'attention and convey a point,supported or not by a bit of clowning in the classroom or the TV studio.But then things start to go wrong:the sponge becomes the air! Reaumur,in A very common idea is to consider air as being like cotton,like wool,like a Memoirs of the sponge,and much more spongious even than any other bodies or collections of French]Royal Academy of bodies to which they may be compared.This idea is particularly adequate to Sciences,1731. explain why air can also become extremely rarefied,and occupy a volume Quoted by considerably bigger than what we had seen it occupy a moment before. Bachelara,p.74. Air is like a sponge,so air expands like a sponge!And now comes none other than Benjamin Franklin,who finds sponges so convincing as to use them to explain . electricity.If matter is like a sponge,electric current must of course be like a liquid that flows through a sponge: B.Franklin,in Common matter is a kind of sponge for the electric fluid.A sponge could not “Experiences and receive water if the parts which make up the water were bigger than the pores observations on electricity, of the sponge;it would only receive it very slowly if there was no mutual expressed in several attraction between its parts and the sponge's parts,the sponge would fill up letters to p. faster if the mutual attraction between the water's parts did not create an Collinson of obstacle,requiring that some force be applied to separate them,finally,the London's Royal Societ”.Translated filling up would be very fastif,instead of attraction,there was mutual repulsion back from the 1752 between the water's parts,concurring with the sponge's attraction.This is the French text quoted in precise situation with electrical matter and common matter. Rachelara n 77 Comments Bachelard:"Franklin only thinks in sponge terms.The sponge,for him, [has become]an empirical category."He adds,with a touch of mockery:"Perhaps,in his youth,[Franklin]had marveled at such a simple object [the sponge].I have often surprised children being fascinated by the sight of a blotter adrinking ink". The Reaumur and Franklin quotations were not culled from a Usenet posting by an undergraduate who has yet to be taught to pour a few drops of intellectual rigor into his enthusiasm.They emanate from intellectual giants of their time,each of them responsible for decisive scientific advances.They should serve as a sobering influence when we discuss software concepts,and help us keep things in perspective the next time we see an author getting a bit carried away by his own analogies. 19.4 THE IMPORTANCE OF BEING HUMBLE One final word of general advice as we prepare to study specific rules of design.To produce great products,designers,even the best ones,should never overestimate the value of their experience.Every ambitious software project is a new challenge:there are no sure recipes The design of a large software product is an intellectual adventure.Too much self- confidence can hurt.The more books you have read(or written),the more classes you have taken (or taught),the more programming languages you know (or designed),the more O-O§19.4 THE IMPORTANCE OF BEING HUMBLE 673 understand the nature of air, the great physicist-philosopher Réaumur used the then common metaphor of a sponge — which, as Bachelard shows, goes back at least to Descartes. Why not? Many good physics teachers occasionally resort to such gimmicks to capture students’ attention and convey a point, supported or not by a bit of clowning in the classroom or the TV studio. But then things start to go wrong: the sponge becomes the air! A very common idea is to consider air as being like cotton, like wool, like a sponge, and much more spongious even than any other bodies or collections of bodies to which they may be compared. This idea is particularly adequate to explain why air can also become extremely rarefied, and occupy a volume considerably bigger than what we had seen it occupy a moment before. Air is like a sponge, so air expands like a sponge! And now comes none other than Benjamin Franklin, who finds sponges so convincing as to use them to explain … electricity. If matter is like a sponge, electric current must of course be like a liquid that flows through a sponge: Common matter is a kind of sponge for the electric fluid. A sponge could not receive water if the parts which make up the water were bigger than the pores of the sponge; it would only receive it very slowly if there was no mutual attraction between its parts and the sponge’s parts; the sponge would fill up faster if the mutual attraction between the water’s parts did not create an obstacle, requiring that some force be applied to separate them; finally, the filling up would be very fast if, instead of attraction, there was mutual repulsion between the water’s parts, concurring with the sponge’s attraction. This is the precise situation with electrical matter and common matter. Comments Bachelard: “Franklin only thinks in sponge terms. The sponge, for him, [has become] an empirical category.” He adds, with a touch of mockery: “Perhaps, in his youth, [Franklin] had marveled at such a simple object [the sponge]. I have often surprised children being fascinated by the sight of a blotter «drinking» ink”. The Réaumur and Franklin quotations were not culled from a Usenet posting by an undergraduate who has yet to be taught to pour a few drops of intellectual rigor into his enthusiasm. They emanate from intellectual giants of their time, each of them responsible for decisive scientific advances. They should serve as a sobering influence when we discuss software concepts, and help us keep things in perspective the next time we see an author getting a bit carried away by his own analogies. 19.4 THE IMPORTANCE OF BEING HUMBLE One final word of general advice as we prepare to study specific rules of design. To produce great products, designers, even the best ones, should never overestimate the value of their experience. Every ambitious software project is a new challenge: there are no sure recipes. The design of a large software product is an intellectual adventure. Too much self￾confidence can hurt. The more books you have read (or written), the more classes you have taken (or taught), the more programming languages you know (or designed), the more O-O Réaumur, in Memoirs of the [French] Royal Academy of Sciences, 1731. Quoted by Bachelard, p. 74. B. Franklin, in “Experiences and observations on electricity, expressed in several letters to P. Collinson of London’s Royal Society”. Translated back from the 1752 French text quoted in Bachelard, p. 77