The answer is remarkable.It is due to a 'crotchet of philosophers'(17)--a crotchet,moreover,not only unsupported by,but opposed to,all the evidence.It appeared first with Empedocles;it produced the 'gnostic reasons'of the Platonists;the 'pre-existing species'of Avicenna;the common intellect of Themistius and Averroes;the 'intentional species'of the schools;the 'occasional causes'of the Cartesians;the predetermined harmony of Leibniz;the plastic medium of Cudworth and the phenomena of Kant.When so many masters of thought have inVented theories it is unhappily easy to believe that they have all gone wrong;but one would at least infer that there was some difficulty to be solved.And yet all these fabrics of sham philosophy are founded upon a 'baseless fancy,'which Reid alone was too independent to take for granted.That 'fancy'was that the 'relation of knowledge inferred an analogy of existence.'(18)Norris of Bemerton had urged that a direct perception of matter was impossible because 'material objects'are removed from the mind 'by the whole diameter of Being.'Reid,with 'an ignorance wiser than knowledge,'confessed his inability to understand this argument.Seeing no difficulty in supposing an immediate perception of a totally disparate thing,he did not make an 'irrational attempt to explain what is in itself inexplicable.'(19)We can no more know how the mind is conscious of itself than how it is percipient of its contrary.The whole puzzle,then,is gratuitous;--which is a consoling result for ordinary common-sense.
Philosophers had thus bewildered themselves by refusing to admit a plain,though ultimate,fact.There is a gulf between mind and matter over which no bridge can be thrown,but no bridge is wanted.The attempt to construct one is superfluous.Yet in a different form the question is still prominent,and modern science has invested it with fresh interest.How are we to conceive of the relation between the mental and the material spheres?How,after all,do we draw the line between things and thoughts,object and subject,ego and non-ego?Where do we reach the impassable gulf,and what,therefore,is the precise sense in which we must pronounce all attempt at bridging it to be preposterous?Hamilton's first position is that we are bound to stand by 'consciousness.'The 'watchword'of the Natural Realist is 'the facts of consciousness,the whole facts and nothing but the facts.'(20)He constantly appeals to the 'deliverance of consciousness,'and assures us again and again that unless we can believe this deliverance,we must suppose man to have been formed only to 'become the dupe and victim of a perfidious creator.'(21)The error of the Cosmothetic Idealists consisted precisely in the arbitrary rejection of a truth given by the testimony of consciousness.An original conviction is to be distinguished from derivative knowledge,as he tells us,by various characteristics,among which is especially its 'necessity.'We cannot really resist it.(22)If a disbelief in consciousness be impossible,why argue against it?If not impossible,how can you assert that the belief is necessary?You have only to state the belief and,on your showing,it will prove itself.To this Hamilton answers that 'necessity'may be of two kinds.We cannot believe a self-contradictory statement;and we are therefore sufficiently guarded by logic against errors which are in this sense impossible.But there are other assertions which may be denied without self-contradiction,and of which,notwithstanding this,the denial would lead to universal scepticism.This corresponds apparently to the difference between a statement of fact and a statement of judgment.A false statement of facts may be as consistent as a true statement,and can Only be met by somehow appealing to experience.(23)So far,then,as consciousness assures us of a fact,we may deny it without contradicting ourselves;but yet,by denying it,we 'make God a deceiver and the root of our nature a lie.'(24)We may thus say without self-contradiction,that memory in general is an illusion,and the world a mere dream or bundle of baseless appearances;(25)but we cannot say so without denying the primary deliverance of consciousness,and striking at the base of all knowledge.Certain truths,though not logically self-supporting,so run through the whole fabric of belief,as to be essential to its existence.If I am conscious,I cannot really doubt the fact of consciousness.The knowledge of the fact and the fact become identical.The possibility of error begins with judgment,or with the interpretation of the fact.It is undeniable,again,that,in some sense or other,I believe in an external world.Every philosopher,as Hamilton says,admits this to be a fact,and Berkeley appeals to the common sense of mankind when denying,as confidently as Reid when affirming,the existence of matter.We must inquire,then,what precisely is this ultimate deliverance.Does consciousness testify merely to the fact of the belief,or also to the truth of the belief;and,in either case,of what belief?This is what Hamilton has to answer,before summoning us to admit the truth on penalty of making God a liar.
