In my interactions with members of our local freethought society, it is simply assumed that science has displaced God. He has become unnecessary because our knowledge of physics, chemistry, cosmology, and biology have grown immensely. Our gaps of knowledge are being filled in, and therefore there is no need for God.
By way of response, I came across this quotation from physicist Luke Barnes, co-author of the wonderful book, A Fortunate Universe: Life in a Finely Tuned Cosmos. He speaks directly to this tendency on the part of atheists to assume that God retreats on the field of battle as scientific knowledge marches forward:
The relationship of God to the Universe is something like that of an author to a book. We won’t find J. K. Rowling in Hogwarts or Shakespeare in fair Verona. We can’t put the author out of a job by discovering a new character, or deciphering the plot, of finding the first page of the book, which reveals how the story started. This is not a hastily revised ‘modern’ God, retreating in the face of science. It predates the scientific revolution by a few thousand years, and for the most part was the worldview of the makers of the scientific revolution.The Christian Philosopher of science and mathematician, John Lennox, makes a similar point in his book, God's Undertaker:
…understanding the mechanism by which a Ford car works is not in itself an argument for regarding Mr. Ford himself as non-existent. The existence of a mechanism is not in itself an argument for the non-existence of an agent who designed the mechanism.How silly would it be for a car mechanic to lift the hood and declare, "I don't see Henry Ford! He must not exist!" In the same way as our scientific knowledge progresses, we do not put God out of a job.
Christian theists do not hold to "god-of-the-gaps" theology that says because we do not understand something, therefore God did it. No serious Christian thinker has ever advocated this position. Rather, God is a necessary being who is the ground of all existence. This view of God has been dominant since Aristotle, who although was not a Christian, he understood the need for a different kind of being to ground all motion and change.
Ironically, even as atheists assert that they are the rational and educated ones, they operate with a view of God that historically no one has ever held. I have found this lack of interaction with serious Christian theism to be a hallmark of the thought of our local freethinkers, thus one of my goals for continuing to join them is to disrupt their echo chamber and to represent (as best I can) the stream of Christian philosophy that they have never interacted with.