Mr. Whewell admits the law in question to be a truth; he only denies that it is a necessary or self-evident truth. Now, if it be not a necessary truth, I should like to know how he has ascertained it to be a truth at all. Has any man ever seen a body put in motion, and continue to move on in a right line forever? Has any man ever ascertained the truth of this law by observation and experiment? It is evident, that if it be true at all, it must be a necessary truth. Who that is capable of rising above the associations of sense, so as to view things as they are in themselves, can meditate upon this subject, without perceiving that the law of _inertia_ is a self-evident truth, necessarily arising out of the very nature of matter? It does not follow, then, that a truth is not "self-evident", because it does not appear so to all men; for some may be blinded to the truth by an illusion of the senses. This is the case, with the necessitarian. He has always seen the motion of body produced by the action of something else; and hence, confounding the activity of mind with the motion of body, he concludes that volition is produced by the prior action of something else. All that he needs in order to see the impossibility of such a thing, is severe and sustained meditation. But how can we expect this from him? Is he not a great reasoner, rather than a great thinker? Does he not display his skill in drawing logical conclusions from the illusions of the senses, and assumptions founded thereon; rather than in laying his foundations and his premises aright, in the immutable depths of meditation and consciousness? We may appeal to his _reason_, and he will fall to _reasoning_. We may ask for _meditation_, and he will give us _logic_. Indeed, he wants that severe and scrutinizing observation which pierces through all the illusions and associations of the senses, rising to a contemplation of things as they are in themselves; which is one of the best attributes of the great thinker.