Sec. 14. The two hypotheses, therefore, are of exactly equivalent value, save that while the one has a certain basis of fact to rest upon,[7] the other is wholly arbitrary. But it may still be retorted, 'Is not that which is _most_ conceivable _most likely_ to be true? and if it is more conceivable that my intelligence is caused by another Intelligence than that it is caused by Non-intelligence, may I not regard the more conceivable hypothesis as also the more probable one? It is somewhat difficult to say how far this argument is, in this case, valid; only I think it is quite evident that its validity is open to grave dispute. For nothing can be more evident to a philosophical thinker than that the substance of Mind must--so far at least as we can at present see--_necessarily_ be unknowable; so that if Matter (and Force) be this substance, we should antecedently expect to find that the actual causal connection should, in this particular case, be more inconceivable than some imaginary one: it would be more natural for the mind to infer that something conceivably more akin to itself should be its cause, than that this cause should be the entity which really gives rise to the unthinkable connection. But even waiving this reflection, and granting that the above argument is _valid_, it is still to an indefinite degree _valueless_, seeing that we are unable to tell _how much it is more likely_ that the more conceivable should here be true than that the less conceivable should be so.