To what extent one finds it in the end convincing depends in part on one's predispositions, something Newman acknowledges. I start from largely the same premises, and thought the book well argued. However, I believe that even one who in the end disagrees would find much of interest in Newman's exposition of degrees and processes of assent.
The book bears out Newman's reputation for lucid prose; the temptation is simply to quote at length. I shall limit myself, though, to some passages from Chapter 5, Section 1. This section, dealing with "Notional Assents", i.e. those not to a fact, ranges such assents from weakest to strongest as Profession, Credence, Opinion, Presumption, and Speculation. It is full of striking passages, as for example the following, from the beginning of the sub-section on Profession, and a paragraph or two in:
There are assents so feeble and superficial, as to be little more than assertions. I class them all together under the head of Profession. Such are the assents made upon habit and without reflection; as when a man calls himself a Tory or a Liberal, as having been brought up as such; or again, when he adopts as a matter of course the literary or other fashions of the day, admiring the poems, or the novels, or the music, or the personages, or the costume, or the wines, or the manners, which happen to be popular, or are patronized in the higher circles. Such again are the assents of men of wavering restless minds, who take up and then abandon beliefs so readily, so suddenly, as to make it appear that they had no view (as it is called) on the matter they professed, and did not know to what they assented or why.I have occasionally been struck with what seems to me the cast of mind of some American politicians, church-going men whose temperament seems to owe more to the Old Testament than the New, to confidence, let us say, rather than repentance. Newman offers a hint in the section on Credence, though he is writing of England, and sounds not unlike Emerson in English Traits:
... This practice of asserting simply on authority, with the pretence and without the reality of assent, is what is meant by formalism. To say "I do not understand a proposition, but I accept it on authority,” is not formalism, but faith; it is not a direct assent to the proposition, still it is an assent to the authority which enunciates it; but what I here speak of is professing to understand without understanding. It is thus that political and religious watchwords are created; first one man of name and then another adopts them, till their use becomes popular, and then every one professes them, because every one else does.
Thus, instances occur now and then, when, in consequence of the urgency of some fashionable superstition or popular delusion, some eminent scientific authority is provoked to come forward, and to set the world right by his "ipse dixit." He, indeed, himself knows very well what he is about; he has a right to speak, and his reasonings and conclusions are sufficient, not only for his own, but for general assent, and, it may be, are as simply true and impregnable, as they are authoritative; but an intelligent hold on the matter in dispute, such as he has himself, cannot be expected in the case of men in general. They, nevertheless, one and all, repeat and retail his arguments, as suddenly as if they had not to study them, as heartily as if they understood them, changing round and becoming as strong antagonists of the error which their master has exposed, as if they had never been its advocates. If their word is to be taken, it is not simply his authority that moves them, which would be sensible enough and suitable in them, both apprehension and assent being in that case grounded on the maxim "Cuique in arte suâ credendum," but so far forth as they disown this motive, and claim to judge in a scientific question of the worth of arguments which require some real knowledge, they are little better, not of course in a very serious matter, than pretenders and formalists.
What Scripture especially illustrates from its first page to its last, is God’s Providence; and that is nearly the only doctrine held with a real assent by the mass of religious Englishmen. Hence the Bible is so great a solace and refuge to them in trouble. I repeat, I am not speaking of particular schools and parties in England, whether of the High Church or the Low, but of the mass of piously-minded and well-living people in all ranks of the community.I will end by quoting a couple of paragraphs from the section on Presumption:
By Presumption I mean an assent to first principles; and by first principles I mean the propositions with which we start in reasoning on any given subject-matter. They are in consequence very numerous, and vary in great measure with the persons who reason, according to their judgment and power of assent, being received by some minds, not by others, and only a few of them received universally. They are all of them notions, not images, because they express what is abstract, not what is individual and from direct experience.
However, if I must speak my mind, I have another ground for reluctance to speak of our trusting memory or reasoning, except indeed by a figure of speech. It seems to me unphilosophical to speak of trusting ourselves. We are what we are, and we use, not trust our faculties. To debate about trusting in a case like this, is parallel to the confusion implied in wishing I had had a choice if I would be created or no, or speculating what I should be like, if I were born of other parents. “Proximus sum egomet mihi.” Our consciousness of self is prior to all questions of trust or assent. We act according to our nature, by means of ourselves, when we remember or reason. We are as little able to accept or reject our mental constitution, as our being. We have not the option; we can but misuse or mar its functions. We do not confront or bargain with ourselves; and therefore I cannot call the trustworthiness of the faculties of memory and reasoning one of our first principles.