The general validity of the arguments is unimpeachable,and the vigour of statement deserves all commendation.Mill puts victoriously the case for the entire freedom of thought and discussion.The real generosity of sentiment,and the obvious sincerity which comes from preaching what he had practised,gives new force to well-worn topics.The interest of the race not only requires the fullest possible liberty to form and to communicate our own opinions,but rather makes the practice a duty.Though Mill gives the essential reasons,his presentation of the case has significant peculiarities.Even if an opinion be true,he says,it ought to be open to discussion.He proceeds to urge the more doubtful point,that contradiction,even when the truth is contradicted,is desirable in itself.Free discussion not only destroys error,but invigorates truth.It preserves a wholesome intellectual atmosphere,which kills the weeds and stimulates the healthy growths.In mathematical reasoning,indeed,the evidence is all on one side.There are no objections,and no answers to objections.But as soon as we reach any question of the truths even of physical,and still more of the moral,sciences,truth must be attained by balancing 'two sets of conflicting reasons.'(11)The doctrine,true or false,which is not contradicted,comes to be held as a 'dead belief.'An objector is supposed to observe that on this showing,the existence of error is necessary to the vitality of truth,and that a belief must perish just because it is unanimously accepted.Mill 'affirms no such thing.'He admits 'that the stock of accepted truths must increase.'But the growth of unanimity,though 'inevitable and indispensable,'has its drawbacks.It would be desirable to encourage contradiction even by artificial contrivances.The Socratic dialectics and the school disputations more or less supplied a want which we have now no means of satisfying.(12)By systematic discussion of first principles,men are forced to understand the full bearing and the true grounds of their professed beliefs.This doctrine is illustrated,and no doubt was derived in part from the early discussions in which Mill had trained his logical powers.It suggests a valuable mode of mental discipline;but as a statement of the conditions of belief,it seems to confuse the accident with the essence.The bare fact of sincere contradiction surely tends to weaken belief;and resistance to contradiction,though it measures the strength of belief,is not the cause of its strength.No doubt a truth may be strengthened in passing through the ordeal of contradiction,so far as we are thus forced to realise its meaning.The same result may be produced by other means,and,above all,by applying belief to practice.We believe in arithmetical truths,partly because the oftener we have to count the more we realise the truth that two and two make four.Whatever the original source of our beliefs,the way to make them vivid is to act upon them.Mill himself incidentally observes that men have a living belief in religious doctrines,'just up to the point to which it is usual to act upon them.'(13)That,I take it,hits the point.The doctrine,for example,that we should turn the second cheek is practically superseded,not because it is never contradicted,but because it does not correspond to our genuine passions or actions.Beliefs,true or erroneous,preserve their vitality so long as they are put into practice,and not the less because they are held unanimously.What is true is that they are then rather instincts than opinions.Beliefs do not die when unchallenged,but are the more likely to be 'dormant'or held implicitly without conscious formulation.
This leads to a further result.As Mill insists in the Logic,'verification'is an essential part of proof.To act upon a belief is one way of verifying.The fact that we apply a theory successfully is also a valid proof that it is true in the great mass of everyday knowledge.But a religious belief is not verified in the same sense.The fact that I act upon it,and am satisfied with my action,proves that it is in harmony with my emotions,not that it is a true statement about facts.The persuasive force often remains,though the logic has become unsatisfactory.This suggests the question as to the nature of a satisfactory 'verification.'We clearly hold innumerable beliefs which we have not fully tested for ourselves.Mill supposes his opponent to urge that simple people must take many things on trust.(14)We might rather say that even the wisest has to take nine-tenths of his beliefs on trust.We may rightly believe many truths which we are incompetent either to discover or to prove directly because we can verify them indirectly.We can accept whole systems of truth,though we are unable to follow the direct proofs.A belief in astronomical theories,for example,is justified for the vast majority,not because they can understand the arguments of Laplace or Newton,but because they may know how elaborately and minutely the conclusions of astronomers are daily verified.The question is not whether we should take things on trust;we cannot help it;but upon what conditions our trust becomes rational.Authority cannot simply justify itself;but it is reasonable to trust an authority which challenges constant examination of its credentials and thorough verification of its conclusions.
