In this and in later writings on political economy it has been well remarked that 'he bent the whole energies of his thought, not so much on its abstruser theories, as on those practical and vital problems which tend to meet the difficulties and ameliorate the condition of the working classes.' 'He was the first political economist,' says Mr. Dodds, 'who seized with a forethought and philanthropy equally before his time upon _the condition-of-the-people question_, as the paramount, the coming question of the age.' His opinion as to the dynamic by which the desired change was to come underwent a great change when his religious views changed; at the present stage he hoped that the forces of reason would gradually effect the desired improvement; afterwards he saw that these forces would be of little avail without the power of the Gospel.
But a more important publication had now come into his horizon. One of his friends, Dr. (afterwards Sir David) Brewster, was at this time engaged in editing a voluminous work, the _Edinburgh Encyclopaedia_. Chalmers was engaged to contribute several articles, chiefly on mathematical subjects. After the death of his sister Barbara (in 1808) he wrote to the editor requesting that the article on 'Christianity' should be assigned to him. Probably he felt, after what he had seen at the two deathbeds in his family, that he needed to make this great subject a matter of more careful study. His own belief in the divine origin of Christianity had been firmly established long before--the historical evidence, as presented by Paley, and the analogical confirmation of it by Butler appearing to him irresistible. As it turned out, his article in the _Encyclopaedia_ bore mainly on the evidences; and the historical evidence received by far the most prominent place. Indeed, he was disposed to lay little stress on what was known as the internal evidence. This arose out of the fear he entertained lest men would substitute their own impressions of Christianity for the clear, authoritative declarations of God. Since God had uttered His voice, the sole and simple duty of men was to ascertain what He had spoken, and give it their profound and absolute acceptance. If they began to discuss the quality of His message, even though its supreme excellence should be the point insisted on, they would be bringing their own judgment into the case, and that might prove a very dangerous element. It needs hardly to be pointed out that in this position Chalmers placed himself in antagonism to the current view of the friends of Christianity. In point of fact, the internal evidence is that which carries conviction to the great mass of believers. At the present day, the character of Jesus Christ stands far the highest and most impressive of all the evidences. Chalmers was influenced, by a mental tendency which clung to him more or less all his life, to dwell on one side of a truth, which, to be fully set forth, needed to be viewed in a variety of lights. But after a time he came to see that the internal evidence deserved a higher place than he had assigned to it. When his article was expanded into his treatise on the _Evidences of Christianity_, the internal branch was duly acknowledged.
But before the article was finished, Chalmers, who was then in his thirtieth year, passed through the ordeal of a very severe illness, which confined him to his room for four months, prevented him from entering his pulpit for six months, and affected him more or less for a whole year. He believed that he was about to die. The whole subject of religion assumed a new aspect of importance in his eyes. He came to see that he had been living without God, and the discovery appalled him. The will of God now became an imperative rule to him, and every energy was bent towards bringing his own heart and life into conformity to it. In such a man as Pascal the sublime transition had been made from the highest walks of mathematical science to the still higher walk of faith. Might not he be able to realise what Pascal had achieved? For a whole year Chalmers laboured to effect this change. His friends could not fail to mark the difference. Brief but solemn allusions such as they had never heard before would drop from his lips. But in many respects he was still the same. 'There were the same cordial greetings, the same kindly questionings about themselves and all their friends, and the same hearty laugh at the racy anecdote or stroke of quiet humour; for, great as was the change effected, neither at the first nor ever afterwards did it damp or narrow that genial and most social spirit which carried him into varied intercourse with all classes of his fellow-men, and made the joy of that intercourse to be a very cordial to his heart.' But, deeply solemnised though he was, he had not attained the peace that passeth understanding, nor had he learned the precious act of free and loving fellowship with his Father in heaven.