external world. And yet what are objects in the external world without
a subject to know them?[16] And what are the hypotheses which science
frames in order to explain phenomena but syntheses of factors framed in
consciousness?[17] What are laws of Nature but mental constructions
framed concerning similar ways of behaviour on the part of a large
number of objects? What are the fundamental conceptions which serve as
the very groundwork of the whole of science but concepts which are
explanations of phenomena and not themselves phenomena?[18]

Wherever we look, we find that our view [p.64] of Nature is in the first
place a result as well as a conviction of the content of consciousness;
that we do not perceive things and their qualities in a form of
immediacy, but only after they have entered into consciousness are we
able to know what external objects really are. The constructions of
science in the form of hypotheses and laws are a proof that the reality
of the physical world and its meaning are known only in so far as they
are known by mind, and in so far as the _universal_ (which is a mental
content) explains the _particular_ (which may or may not be an object in
the external world).

Eucken emphasises this truth in several of his books, and whenever the
truth is borne in mind the scientist becomes aware of the existence of a
reality beyond that of the objects of sense. And even when the scientist
is unaware of the mental qualities which operate in perceiving external
objects and of the generalisations formed as the result of the
impressions left by the objects in the mind, he uses these all the same.
Professor Haeckel (one of Professor Eucken's colleagues in Jena) starts
out in _The Riddle of the Universe_ with the strong hope of reducing the
whole universe (including God) into a state of material substance, and
ends with a kind of peroration on the virtues of the new goddesses, the