Economics is not politics. One is a science, concerned with the immutable and constant laws of nature that determine the production and distribution of wealth; the other is the art of ruling.

You will perceive that economy, scientifically speaking, is a very contracted science; it is in fact a sort of vague mathematics which calculates the causes and effects of man's industry, and shows how it may be best applied. There are a multitude of allied branches of knowledge connected with mans condition; the relation of these to political economy is analogous to the connexion of mechanics, astronomy, optics, sound, heat, and every other branch more or less of physical science, with pure mathematics.

Political Economy or Economics is a study of mankind in the ordinary business of life; it examines that part of individual and social action which is most closely connected with the attainment and with the use of the material requisites of wellbeing.

Economics is a social science, not a physical science.

Economics is the study of how society manages its scarce resources. In most societies, resources are allocated not by an all-powerful dictator but through the combined actions of millions of households and firms.

Economics is a study of cause-and-effect relationships in an economy. It's purpose is to discern the consequences of various ways of allocating resources which have alternative uses. It has nothing to say about philosophy or values, anymore than it has to say about music or literature.

Economic and political developments have forced upon us a great problem of analysis in the field of politico-economic organization. The center of this problem lies in the midground between the science of politics and the science of economics and its scope is coterminous with the scope of both. It demands the best minds of both science to forge a new pattern of thinking which will weld the elements of politics and economics into an integrated whole having validity in the present day.

POLITICAL economy, considered as a branch of the science of a statesman or legislator, proposes two distinct objects: first, to provide a plentiful revenue or subsistence for the people, or more properly to enable them to provide such a revenue or subsistence for themselves; and secondly, to supply the state or commonwealth with a revenue sufficient for the public services. It proposes to enrich both the people and the sovereign.

Economics is a science of thinking in terms of models joined to the art of choosing models which are relevant to the contemporary world. It is compelled to be this, because, unlike the typical natural science, the material to which it is applied is, in too many respects, not homogeneous through time. The object of a model is to segregate the semi-permanent or relatively constant factors from those which are transitory or fluctuating so as to develop a logical way of thinking about the latter, and of understanding the time sequences to which they give rise in particular cases.
Good economists are scarce because the gift for using "vigilant observation" to choose good models, although it does not require a highly specialised intellectual technique, appears to be a very rare one.

Economics is that way of understanding behavior that starts from the assumption that people have objectives and tend to choose the correct way to achieve them.

As conceived in this book, economics is the science of rational choice in a world─our world─in which resources are limited in relation to human wants. The task of economics, so defined, is to explore the implications of assuming that man is a rational maximizer of his ends in life, his satisfactions─what we shall call his “self-interest.” Rational maximization should not be confused with conscious calculation. Economics is not a theory about consciousness. Behavior is rational when it conforms to the model of rational choice, whatever the state of mind of the chooser.(...) Nor is perfect rationality assumed; rational-choice theory allows us to assume that rationality is “bounded” because of human cognitive limitations, although another way to think of those limitations is as costs of absorbing and using information.

Political Economy means that everybody except politicians must be economical.

Economics is not an exact science.

[E]conomics can never be a science in the sense that physics or chemistry is. There are many different types of economic theory, each emphasizing different aspects of a complex reality, making different moral and political value judgments and drawing different conclusions. ...[E]conomic theories constantly fail to predict real-world developments... not least because human beings have... free will, unlike chemical molecules or [other] physical objects.