translate changes in the amount of bonds into changes in long - term interest rates. we know from event studies how policy announcements translate into asset price movements. we have built models of bank intermediation that tell us how tighter funding conditions will impact on bank lending. that ’ s for the science behind it and that ’ s when art, or rather artisanat – craftsmanship – comes in. we need to interconnect these models, and fit them into a general equilibrium view of how the euro area economy evolves dynamically – preferably in a tractable way. we need to know when expert judgment, rather than empirical estimation, has been used. and when this is all done, we should be able to keep track of the key assumptions we have used, and take some distance. to quote from abhijit banerjee and esther duflo : “ we, the economists, are often wrapped up in our models and our methods and sometimes forget where science ends and ideology begins. we answer policy questions based on assumptions that have become second nature to us because they are the building blocks of our models but it doesn ’ t mean that they are always correct ”. we owe this transparency to ourselves as policymakers, and to society as a whole when we communicate our decisions. we don ’ t want to prove right joan robinson ’ s remark that “ the purpose of studying economics is to learn ( … ) how to avoid being deceived by economists ”. economics as a profession these examples say a lot about our profession. they inspire at least four additional pieces of advice that i would like to pass on. first, uncertainty is a pervasive feature of our profession. a first instance of uncertainty is the parameters of our models. to illustrate, let ’ s go back to the phillips curve. the “ missing ” inflation episode of recent years has stirred intense debates on whether the phillips curve still provides valuable policy advice today. according to conventional phillips curve estimates, inflation today should be measurably higher. this raises all sorts of questions that my colleagues are now exploring. did globalisation change the relationship between domestic output and inflation? is there an “ amazon ” effect – that is, is inflation lower because people can buy cheaper online? does workers ’ bargaining power depend on traditional, narrow measures of unemployment or on broader ones including underemployment? does it depend on the quality of jobs being created? and so on. none of these questions have been settled. our

– 67, federal reserve system, september. 14 for more details, see haskel, j. and westlake, s. ( 2017 ), capitalism without capital – the rise of the intangible economy, princeton university press. see also the appendix entitled “ characteristics of intangibles per asset type ” in european commission ( 2017 ), “ investment in the eu member states : an analysis of drivers and barriers ”, european economy institutional papers, no 062, october, p. 80. 15 see popov, a. and roosenboom, p. ( 2012 ), “ venture capital and patented innovation : evidence from europe, ” economic policy, vol. 27 ( 71 ), july, pp. 447 – 482. 16 see “ the opportunities and challenges of fintech ”, speech by governor lael brainard, federal reserve board of governors, at the conference on financial innovation at the board of governors of the federal reserve system, washington, d. c., 2 december 2016 ; and “ the promise of fintech – something new under the sun? ”, speech by mark carney, governor of the bank of england, at the deutsche bundesbank g20 conference on digitising finance, financial inclusion and financial literacy, wiesbaden, 25 january 2017 4 / 4 bis central bankers'speeches