For over a century, social scientists have debated how educational attainment impacts religious belief. In this paper, I use Canadian compulsory schooling laws to identify the relationship between completed schooling and later religiosity. I find that higher levels of education lead to lower levels of religious participation later in life. An additional year of education leads to a 4-percentage-point decline in the likelihood that an individual identifies with any religious tradition; the estimates suggest that increases in schooling can explain most of the large rise in non-affiliation in Canada in recent decades.So are education and religion complements or substitutes? They could be substitutes in that both science and religion try to explain the world around us and as the population becomes more educated the understanding of the scientific explanation grows in the population and this drives out the religious explanation. But they could be complements since many religions place strong emphasis on education and learning. Just think of how many religious based schools and universities there are.
The evidence in the paper suggests that the two are substitutes .... at least for Canadians.