medium of the
subjective, and of regularly arranged laws to which both the subjective and
the objective are commonly subordinate. But why just these and no other
qualities of the subject and of objects exist, why just these and no other
laws reign, why just this and no other relation takes place between the
perceiving subject and the perceived object, would remain unanswered as
before.

Amidst a generation which is so fond of reveling in the thought of an
extension of all the limits of our knowledge, and is inclined to proclaim
as true that which it wishes and hopes, investigators are not wholly
wanting who very decidedly express their consciousness of these limits of
our knowledge, and at the same time combine it with the most logical
scientific reasoning and investigation. Even when in detail they reach
these limits from the most varying points of view, and draw {149} them in
different directions, they all agree in confirming the principle that it is
one of the first and most indispensable conditions of successful
investigation always to be conscious of the limits of its perception.
Voices which remind mankind of these limits, are perhaps less popular, for
man prefers to be reminded of the advances rather than of the limitations
of his knowledge; but they are on that account the more worthy of our
gratitude, for they keep us on the solid ground of the attainable from
which alone sure progress in knowledge is possible. Among such philosophers
we name Ulrici, and especially Lotze; among scientists, in the first place,
two pioneers in their departments--namely, in the department of the
mechanism of heat, Robert von Mayer--compare his "Bemerkungen ueber das
mechanische Aequivalent der Waerme" ("Remarks on the Mechanical Equivalent
of Heat"), and "Ueber nothwendige Consequenzen und Inconsequenzen der
Waermemechanik" ("Necessary Consequences and Inconsequences of the Mechanism
of Heat"), Stuttgart, Cotta;--and in the realm of the development of
organisms, K. E. von Baer--compare his "Reden und kleinere Aufsaetze"
("Addresses and Essays"), 2 vols., St. Petersburg, 1864 and 1876. In this
connection we have already mentioned the name of DuBois-Reymond. Otto
Koestlin published two remarkable dissertations in this direction--"Ueber
die Grenzen der Naturwissenschaft" ("Limits of Natural Science"), Tuebingen,
Fues, 2d ed., 1874, and "Ueber natuerliche Entwicklung" ("Natural
Development"), ib., 1875. In the latter he especially caut