364 SPAEKS FROM A GEOLOGIST'S HAMMER. 



Finally we discern a fourth class of mental states. 

 These are the assumptions which we irresistibly make of 

 an absolute causal relation between certain conscious 

 states and realities external to consciousness. We find in 

 existence an assumption that certain states are caused by 

 sensible phenomena ; and an assumption that other men- 

 tal states are caused by the disclosure of certain abstract 

 truths; and an assumption that these abstract truths have 

 a necessary existence in the universe of which we are a 

 part. We find here, also, the assumption of personal ex- 

 istence and personal identity. This fourth group of con- 

 scious states impresses a belief in the reality of sensible 

 phenomena; in the reality of existence behind these phe- 

 nomena ; in the reality of supersensible existence under- 

 neath all psychic phenomena, and in the reality of truth 

 apprehended as universal and necessary. These subtle, 

 instantaneous and irresistible assumptions are the only 

 bond of connection between us and any realm outside of 

 our own minds. Invalidate them, and all which seems to 

 exist, either in a world without or a world within, re- 

 solves itself into a phantasmagoi'ia of forms without sub- 

 stance, a succession of mental states which seems to have 

 a cause and correlative, but has none; a succession which 

 seems to be concatenated and orderly, but is absolutely 

 chaotic and fortuitous; a succession of states which, after 

 all, are not states, but only the alluring and deceptive 

 images of states, and not even images, for the seeming 

 must be as fanciful and illusory as the seeming of sub- 

 stance. Deny the validity of the assumption of causal 

 correlations between mental states and realities, and all 

 knowledge is annulled. We float only in a glittering 

 realm of empty forms, we cannot say we float, but we 



