We mistake the true meaning of this idea when we regard it as an
enouncement； or even as a hypothetical declaration of the existence of
a real thing； which we are to regard as the origin or ground of a
systematic constitution of the universe。 On the contrary； it is left
pletely undetermined what the nature or properties of this
so…called ground may be。 The idea is merely to be adopted as a point
of view； from which this unity； so essential to reason and so
beneficial to the understanding； may be regarded as radiating。 In
one word； this transcendental thing is merely the schema of a
regulative principle； by means of which Reason； so far as in her lies；
extends the dominion of systematic unity over the whole sphere of
experience。
The first object of an idea of this kind is the ego； considered
merely as a thinking nature or soul。 If I wish to investigate the
properties of a thinking being； I must interrogate experience。 But I
find that I can apply none of the categories to this object； the
schema of these categories； which is the condition of their
application； being given only in sensuous intuition。 But I cannot thus
attain to the cognition of a systematic unity of all the phenomena
of the internal sense。 Instead； therefore； of an empirical
conception of what the soul really is； reason takes the conception
of the empirical unity of all thought； and； by cogitating this unity
as unconditioned and primitive； constructs the rational conception
or idea of a simple substance which is in itself unchangeable；
possessing personal identity； and in connection with other real things
external to it； in one word； it constructs the idea of a simple
self…subsistent intelligence。 But the real aim of reason in this
procedure is the attainment of principles of systematic unity for
the explanation of the phenomena of the soul。 That is； reason
desires to be able to represent all the determinations of the internal
sense as existing in one subject； all powers as deduced from one
fundamental power； all changes as mere varieties in the condition of a
being which is permanent and always the same； and all phenomena in
space as entirely different in their nature from the procedure of
thought。 Essential simplicity （with the other attributes predicated of
the ego） is regarded as the mere schema of this regulative
principle； it is not assumed that it is the actual ground of the
properties of the soul。 For these properties may rest upon quite
different grounds； of which we are pletely ignorant； just as the
above predicates could not give us any knowledge of the soul as it
is in itself； even if we regarded them as valid in respect of it；
inasmuch as they constitute a mere idea； which cannot be represented
in concreto。 Nothing but good can result from a psychological idea
of this kind； if we only take proper care not to consider it as more
than an idea； that is； if we regard it as valid merely in relation
to the employment of reason； in the sphere of the phenomena of the
soul。 Under the guidance of this idea； or principle； no empirical laws
of corporeal phenomena are called in to explain that which is a
phenomenon of the internal sense alone； no windy hypotheses of the
generation； annihilation； and palingenesis of souls are admitted。 Thus
the consideration of this object of the internal sense is kept pure；
and unmixed with heterogeneous elements； while the investigation of
reason aims at reducing all the grounds of explanation employed in
this sphere of knowledge to a single principle。 All this is best
effected； nay； cannot be effected otherwise than by means of such a
schema； which requires us to regard this ideal thing as an actual
existence。 The psychological idea is； therefore； meaningless and
inapplicable； except as the schema of a regulative conception。 For； if
I ask whether the soul is not really of a spiritual nature… it is a
question which has no meaning。 From such a conception has been
abstracted； not merely all corporeal nature； but all nature； that
is； all the predicates of a possible experience； and consequently； all
the conditions which enable us to cogitate an object to this
conception have disappeared。 But； if these conditions are absent； it
is evident that the conception is meaningless。
The second regulative idea of speculative reason is the conception
of the universe。 For nature is properly the only object presented to
us； in regard to which reason requires regulative principles。 Nature
is twofold… thinking and corporeal nature。 To cogitate the latter in
regard to its internal possibility； that is； to determine the
application of the categories to it； no idea is required… no
representation which transcends experience。 In this sphere； therefore；
an idea is impossible； sensuous intuition being our only guide； while；
in the sphere of psychology； we require the fundamental idea （I）；
which contains a priori a certain form of thought namely； the unity of
the ego。 Pure reason has； therefore； nothing left but nature in
general； and the pleteness of conditions in nature in accordance
with some principle。 The absolute totality of the series of these
conditions is an idea； which can never be fully realized in the
empirical exercise of reason； while it is serviceable as a rule for
the procedure of reason in relation to that totality。 It requires
us； in the explanation of given phenomena （in the regress or ascent in
the series）； to proceed as if the series were infinite in itself； that
is； were prolonged in indefinitum；； while on the other hand； where
reason is regarded as itself the determining cause （in the region of
freedom）； we are required to proceed as if we had not before us an
object of sense； but of the pure understanding。 In this latter case；
the conditions do not exist in the series of phenomena； but may be
placed quite out of and beyond it； and the series of conditions may be
regarded as if it had an absolute beginning from an intelligible
cause。 All this proves that the cosmological ideas are nothing but
regulative principles； and not constitutive； and that their aim is not
to realize an actual totality in such series。 The full discussion of
this subject will be found in its proper place in the chapter on the
antinomy of pure reason。
The third idea of pure reason； containing the hypothesis of a
being which is valid merely as a relative hypothesis； is that of the
one and all…sufficient cause of all cosmological series； in other
words； the idea of God。 We have not the slightest ground absolutely to
admit the existence of an object corresponding to this idea； for
what can empower or authorize us to affirm the existence of a being of
the highest perfection… a being whose existence is absolutely
necessary… merely because we possess the conception of such a being？
The answer is： It is the existence of the world which renders this
hypothesis necessary。 But this answer makes it perfectly evident
that the idea of this being； like all other speculative ideas； is
essentially nothing more than a demand upon reason that it shall
regulate the connection which it and its subordinate faculties
introduce into the phenomena of the world by principles of
systematic unity and； consequently； that it shall regard all phenomena
as originating from one all…embracing being； as the supreme and
all…sufficient cause。 From this it is plain that the only aim of
reason in this procedure is the establishment of its own formal rule
for the extension of its dominion in the world of experience； that
it does not aim at an extension of its cognition beyond the limits
of experience； and that； consequently； this idea does not contain
any constitutive principle。
The highest formal unity； which is based upon ideas alone； is the
unity of all things… a unity in accordance with an aim or purpose； and
the speculative interest of reason renders it necessary to regard
all order in the world as if it originated from the intention and
design of a supreme reason。 This principle unfolds to the view of
reason in the sphere of experience new and enlarged prospects； and
invites it to connect the phenomena of the world according to
teleological laws； and in this way to attain to the highest possible
degree of systematic unity。 The hypothesis of a supreme
intelligence； as the sole cause of the universe… an intelligence which
has for us no more than an ideal existence… is accordingly always of
the greatest service to reason。 Thus； if we presuppose； in relation to
the figure of the earth （which is round； but somewhat flattened at the
poles）；* or that of mountains or seas； wise designs on the part of
an author of the universe； we cannot fail to make； by the light of
this supposition； a great number of interesting discoveries。 If we
keep to this hypothesis； as a principle which is purely regulative；
even error cannot be very detrimental。 For； in this case； error can
have no more serious consequences than that； where we expected to
discover a teleological connection （nexus finalis）； only a
mechanical or physical connection appears。 In such a case； we merely
fail to find the additional form of unity we expected； but we do not
lose the rational unity which the mind requir