To have given?

[yjso21]

To have given clear and unified answers in familiar empirical terms to
those theoretical questions which most occupied men's minds at the
time, and to have deduced from them clear practical directives without
creating obviously articifial links between the two, was the principle
achievement of Marx's theory ...

Nowadays I'm readingn a Wikipedia.

This pragraph is part of 'Sociology'

I can't understand To have give... , To have deduced...

What does this form mean?

[emsr2d2]

To have given clear and unified answers in familiar empirical terms to
those theoretical questions which most occupied men's minds at the
time, and to have deduced from them clear practical directives without
creating obviously articifial links between the two, was the principle
achievement of Marx's theory ...

Nowadays I'm readingn a Wikipedia.

This pragraph is part of 'Sociology'

I can't understand To have give... , To have deduced...

What does this form mean?

If you take the words from the very end of the piece and put them at the beginning, you may see how this works:

The principle achievement of Marx's theory was to have given clear and unified answers in familiar ... and to have deduced from them clear practical ... between the two.

So Marx's theory achieved one main objective - clear and unified answers. From those answers, he deduced directives.

[JohnParis]

Your citation comes from a biography of Karl Marx. I hope the following is a correct paraphrasing of the author's thoughts.

The principle achievement of Marx's theory was that he gave clear and unified answers in familiar empirical terms to those theoretical questions which most occupied men's minds at the time, and that he concluded from these answers clear practical directives without creating artificial links between the two. (answers and directives)

I would appreciate suggestions from colleagues.

John