There is an excellent article on gomasons.org that I think is a must-read. Here is a snippet:
The Intersection of Modern Free-Masonry, Humanism, and Secularism
By Bro. Kris Hartung
What do Modern Free-Masonry, Humanism, and Secularism have in common? The answer to this question lies in the analysis of the key principles of these three philosophies, and as we shall see, there is more in common between them than what one might suspect. This essay will demonstrate that Modern Free-Masonry, as exemplified by the Grand Orient of the United States, the Grand Orient of France, and the original Modern Free-Masons of 18th century Europe, are fundamentally humanist and secular in nature, differentiated from Humanism and Secularism by their focus on brotherhood and ritual.
It’s a fascinating article so read on!