First of all I want to remind you of the essential features of models. In my opinion they are: (i) drawing up a list of the variables to be considered; (ii) drawing up a list of the equations or relations the variables have to obey and (iii) testing the validity of the equations, which implies the estimation of their coefficients, if any. As a consequence of especially (iii) we may have to revise (i) and (ii) so as to arrive at a satisfactory degree of realism of the theory embodied in the model. Then, the model may be used for various purposes, that is, for the solution of various problems. The advantages of models are, on one hand, that they force us to present a "complete" theory by which I mean a theory taking into account all relevant phenomena and relations and, on the other hand, the confrontation with observation, that is, reality. Of course these remarks are far from new.
Jan TinbergenRelated topics
account arrive confrontation course degree far force mean model opinion present realism revise satisfactory taking testing validity relations iiiRelated quotes
Among the various paradigmatic changes in science and mathematics in this century, one such change concerns the concept of uncertainty. In science, this change has been manifested by a gradual transition from the traditional view, which insists that uncertainty is undesirable in science and should be avoided by all possible means, to an alternative view, which is tolerant of uncertainty and insists that science cannot avoid it. According to the traditional view, science should strive for certainty in all its manifestations (precision, specificity, sharpness, consistency, etc.); hence, uncertainty (imprecision, nonspecificity, vagueness, inconsistency, etc.) is regarded as unscientific. According to the alternative (or modem) view, uncertainty is considered essential to science; it is not only an unavoidable plague, but it has, in fact, a great utility.
George Klir
Few people seem to perceive fully as yet that the most far-reaching consequence of the establishment of the common origin of all species is ethical; that it logically involved a readjustment of altruistic morals, by enlarging, as a necessity of rightness, the application of what has been called the 'Golden Rule' from the area of mere mankind to that of the whole animal kingdom. Possibly Darwin himself did not quite perceive it. While man was deemed to be a creation apart from all other creations, a secondary or tertiary morality was considered good enough to practise towards the 'inferior' races; but no person who reasons nowadays can escape the trying conclusion that this is not maintainable. And though we may not at present see how the principle of equal justice all round is to be carried out in it entirety, I recognize that the League is grappling with the question.
Thomas Hardy
A word in conclusion about the relations between the whites and blacks. What must be the general character of the intercourse between them? Am I to treat the black man as my equal or my inferior? I must show him that I can respect the dignity of human personality in every one, and this attitude in me he must be able to see for himself; but the essential thing is that there shall be a real feeling of brotherliness. How far this is to find complete expression in the sayings and doings of daily life must be settled by circumstances. The negro is a child, and with children nothing can be done without the use of authority. We must, therefore, so arrange the circumstances of daily life that my natural authority can find expression. With regard to the negroes, then, I have coined the formula: "I am your brother, it is true, but your elder brother."
Albert Schweitzer
I envisaged future generations of Iranians proudly taking their rightful place among the vast family of nations, and fulfilling their responsibilities with dignity. I hoped to see dispelled for ever the medieval shadows from which Iran had emerged only half a century ago, and that the light which is the very essence of Iranian civilization and culture would prevail. Throughout my reign, I lived only for the realization of this dream which was beginning to become reality.
It will be seen that I worked tirelessly and keenly to this end. I had ceaselessly to struggle against all sorts of obstacles and difficulties. I had to confront innumerable plots and intrigues both inside the country and abroad. I combated the all-powerful, multi-national trusts and cartels when all my advisers warned me against such challenges. I may have made mistakes, of course, but this long battle was not one of them.
Muhammad Reza Pahlavi
I am under no illusion that our present strategy of using means short of total war to achieve our ends and oppose communism is a guarantee that a world war will not be thrust upon us. But a policy of patience and determination without provoking a world war, while we improve our military power, is one which we believe we must continue to follow....
Under present circumstances, we have recommended against enlarging the war from Korea to also include Red China. The course of action often described as a limited war with Red China would increase the risk we are taking by engaging too much of our power in an area that is not the critical strategic prize.
Red China is not the powerful nation seeking to dominate the world. Frankly, in the opinion of the Joint Chiefs of Staff, this strategy would involve us in the wrong war, at the wrong place, at the wrong time, and with the wrong enemy.
Omar Bradley