In my youth I was much disposed to contemplation, and at my commencement in manhood I committed to manuscript such sentiments or arguments as appeared most consonant to reason, lest through the debility of memory, my improvement should have been less gradual. This method of scribbling I practised for many years, from which I experienced great advantages in the progression of learning and knowledge; the more so as I was deficient in education and had to acquire the knowledge of grammar and language, as well as the art of reasoning, principally from a studious application to it; which after all, I am sensible, lays me under disadvantages, particularly in matters of composition; however, to remedy this defect I have substituted the most unwearied pains.... Ever since I arrived at the state of manhood and acquainted myself with the general history of mankind, I have felt a sincere passion for liberty. The history of nations doomed to perpetual slavery in consequence of yielding up to tyrants their natural-born liberties, I read with a sort of philosophical horror.
In Allen's youth great revivals were inaugurated, organized, and continued mainly by the preaching of Whitefield, who roused and electrified audiences of several thousands, as men have rarely been moved since the days of Peter the Hermit. Even Franklin, Bolingbroke, and Chesterfield were fascinated by him. As for Allen, baptized in his infancy, in the days when no Sabbath-school blessed the race, when the Westminster Catechism and Watts' Hymns were in use throughout New England (Isaac Watts died when Allen was eleven years old), living in and near northwest Connecticut in as democratic and religious community as the world had ever seen, reading none of the books of the Deists, he was fond of discussion and delighted in writing out his arguments. Having been brought up an Armenian Christian, in contradistinction to a Calvinistic Christian, his views in early manhood began to change. One picture of this gradual evolution he gives us in the following description:
The doctrine of imputation according to the Christian scheme consists of two parts. First, of imputation of the apostasy of Adam and Eve to their posterity, commonly called original sin; and secondly, of the imputation of the merits or righteousness of Christ, who in Scripture is called the second Adam to mankind or to the elect. This is a concise definition of the doctrine, and which will undoubtedly be admitted to be a just one by every denomination of men who are acquainted with Christianity, whether they adhere to it or not.
I therefore proceed to illustrate and explain the doctrine by transcribing a short but very pertinent conversation which in the early days of my manhood I had with a Calvinistic divine; but previously remark that I was educated in what are commonly called the Armenian principles; and among other tenets to reject the doctrine of original sin; this was the point at issue between the clergyman and me. In my turn I opposed the doctrine of original sin with philosophical reasonings, and as I thought had confuted the doctrine. The Reverend gentleman heard me through patiently: and with candor replied:
"Your metaphysical reasonings are not to the purpose, inasmuch as you are a Christian and hope and expect to be saved by the imputed righteousness of Christ to you; for you may as well be imputedly sinful as imputedly righteous. Nay," said he, "if you hold to the doctrine of satisfaction and atonement by Christ, by so doing you presuppose the doctrine of apostasy or original sin to be in fact true;" for, said he, "if mankind were not in a ruined and condemned state by nature, there could have been no need of a Redeemer; but each individual of them would have been accountable to his Creator and Judge, upon the basis of his own moral agency. Further observing that upon philosophical principles it was difficult to account for the doctrine of original sin, or of original righteousness; yet as they were plain, fundamental doctrines of the Christian faith we ought to assent to the truth of them; and that from the divine authority of revelation. Notwithstanding," said he, "if you will give me a philosophical explanation of original imputed righteousness, which you profess to believe and expect salvation by, then I will return you a philosophical explanation of original sin; for it is plain," said he, "that your objections lie with equal weight against original imputed righteousness, as against original imputed sin."
Upon which I had the candor to acknowledge to the worthy ecclesiastic, that upon the Christian plan I perceived the argument had clearly terminated against me. For at that time I dared not to distrust the infallibility of revelation; much more to dispute it. However, this conversation was uppermost in my mind for several months after; and after many painful searches and researches after the truth, respecting the doctrine of imputation, resolved at all events to abide the decision of rational argument in the premises; and on a full examination of both parts of the doctrine, rejected the whole; for on a fair scrutiny, I found that I must concede to it entirely or not at all; or else believe inconsistently as the clergyman had argued.
He relates also a change from his juvenile views of biblical history:
When I was a boy, by one means or other, I had conceived a very bad opinion of Pharaoh; he seemed to me to be a cruel, despotic prince; he would not give the Israelites straw, but nevertheless, demanded of them the full tale of brick; for a time he opposed God Almighty; but was at last luckily drowned in the Red Sea; at which event, with other good Christians, I rejoiced, and even exulted at the overthrow of the base and wicked tyrant. But after a few years of maturity and examination of the history of that monarch given by Moses, with the before recited remarks of the apostle, I conceived a more favorable opinion of him; inasmuch as we are told that God raised him up and hardened his heart, and predestinated his reign, his wickedness, and his overthrow.
In 1782 he says:
In the circle of my acquaintance (which has not been small), I have generally been denominated a Deist, the reality of which I never disputed; being conscious I am no Christian, except mere infant baptism makes me one; and as to being a Deist, I know not, strictly speaking, whether I am one or not, for I have never read their writings.