Watts, Robert (1820–95), presbyterian scholar, was born 10 July 1820 in Moneylane, near Dundrum, Co. Down, youngest among fourteen children; nothing further is known of his family background. He attended RBAI for a time, but (probably as a result of his father's death) went with his mother to join two elder brothers in the US, and there attended Lafayette College, Pennsylvania, and graduated MA (1849) from Washington College, Virginia. All his life he was greatly influenced by his studies in theology in Princeton, New Jersey, and was ordained a minister in the presbyterian church in Philadelphia in 1853. He organised a mission in that city in 1853; it was erected in 1856 into a congregation called Westminster church, with Watts as its first minister. On a visit to Ireland he married (6 September 1853) Margaret, daughter of William Newell of Summerhill, Tullymurry, Co. Down, but when her health failed in 1861 she returned to Ireland.
In 1863, while visiting Ireland, Watts was called by Lower Gloucester St. (later Clontarf) in Dublin to be their minister, and resigned from his Philadelphia congregation. He was installed August 1863, and resigned October 1866, when he became professor of systematic theology at Assembly's College, Belfast. In 1864 he was awarded the degree of DD by Westminster College, Missouri. He was an inspiring lecturer, who sought to uphold in Belfast the standard of orthodoxy he had admired in Princeton; he was described as more Calvinist than Calvin, and the college's conservative theology attracted even students from the Free Church in Scotland. He vigorously opposed any tendency in contemporary theological scholarship that would have led to questioning of the infallible authority of the Bible.
His stance in the important debate on the relation between science and religion derived likewise from his conviction that the last word on all such matters was to be found in the biblical record. He offered to deliver a paper in the section on biology at the meeting of the British Association in Belfast in August 1874, in which he proposed to try to make peace between revealed religion and the new and potentially divisive theory of evolution; when his paper, and thus the offer of peace (on Watts's terms), were rejected, Watts was angered. His opposition to modern science was deepened at the meeting by the presidential address of John Tyndall (qv). This speech became immediately notorious; Tyndall's forthright rejection of religion's right to intervene in scientific matters produced impassioned sermons throughout Belfast, and provoked Watts to make a swingeing attack on the materialism of Tyndall in particular and of science in general. Watts delivered his sermon on 23 August 1874 and later expanded it as Atomism . . . (1875). In this pamphlet Watts also managed to deliver a side-swipe against another long-standing adversary, the catholic hierarchy, even though the bishops, equally opponents of scientific materialism, could (if only in a parallel universe) have become his natural allies.
In 1880 Watts was elected moderator of the general assembly and was the leading figure in a deputation that went to London to discuss with government the need for theological degrees to be available to presbyterians in Ireland. After some delay caused by a change of government, their petition was granted in 1881. Such publications as The rule of faith and the doctrine of inspiration (1885) and The sovereignty of God (1894) reveal Watts's unswerving support of conservative beliefs. He died in Belfast 26 July 1895. His elder son, a minister, predeceased him. There were also two or possibly three daughters who married ministers, possibly men who as students had attended weekly soirées in the Watts home. A portrait was presented to Assembly's College, Belfast.