Psychology shifted away from pure theory and towards more careful and systematic empirical observation.

心理学从纯理论研究转向了更加细致系统化的实证观察。

But all our talk was limited to pure theory and nothing else.

但我们的讨论仅限于纯理论，没有其他内容。

These purely theoretical concepts led the way to  atomic theory and the unfulfilled biology field.

这些纯理论概念引领了原子理论未实现的生物学领。

But many participants in The Republic of Letters were focused on less theoretical matters.

，“书共”的许多参与者更关注的是实际非纯理论的问题。

This is a question for historical generalisation rather than for pure theory.

这是历史概括的问题，不是纯理论的问题。

Why did they satisfy themselves with the meager theory of positive external effects as a corollary of the equally pitiable theory of pure and perfect competition?

为何他们满足于将正外部效应这一贫乏理论作为同样可悲的纯理论完全竞争理论的附属品呢？

I don't think that was wrong, you know, back months ago, to highlight in pure theory, a one-time tariff is a one-time increase in cost.

我认为几个月前从纯理论的角度强调一次性关税是一次性成本增加并没有错。

In the other kind of practical books, the kind dealing mainly with the principles underlying rules, the major propositions and arguments will, of course, look exactly like those in a purely theoretical book.

在另一类实用书籍，主要涉及规则背后的原理、主要命题论证的书籍，当看起来与纯理论书籍的完全相同。

In the case of purely theoretical books, the criteria for agreement or disagreement relate to the truth of what is being said.

对于纯理论书籍，同意或不同意的标准与所讲内容的真实性有关。