The Light upon the Candlestick (1662) was written by a Dutch Collegiant, but was taken by the Quakers to be a good account of their own theory of knowledge. Yet a contemporary scholar of Dutch Collegiant thought interprets this same essay as showing the beginning of the Collegiants’ moving away from a spiritualist interpretation of the Light Within and towards a rationalist interpretation, influenced by the philosopher Spinoza. While the title page of this essay indicates the influence of a Quaker, it seems that, until now, no one has examined this connection in detail. A recent translation of William Ames’ Mysteries of the Kingdom of God 1661) has now made this comparison possible. The comparison shows that the Quaker influence is substantial, and that The Light upon the Candlestick is better interpreted as a point of convergence between Quaker and Collegiant thought than as a rationalist turn in Collegiant thought.