Thank you for your question to TruthBook.com. You can find good definitions for both of these words if you like from Google…my reply is in context of The Urantia Book. Here is the quote in which this phrase is contained:

12:9.5 Your religion is becoming real because it is emerging from the slavery of fear and the bondage of superstition. Your philosophy struggles for emancipation from dogma and tradition. Your science is engaged in the agelong contest between truth and error while it fights for deliverance from the bondage of abstraction, the slavery of mathematics, and the relative blindness of mechanistic materialism.

If we were to define the predominant philosophy influencing the world today it would be “mechanistic” as opposed to created by a divine plan. Science is mechanistic – -it’s not in touch with any spiritual foundation or Creative Being responsible for creation. The Big Bang is mechanistic. Atheism and free thinking are on the rise and use science as their god. In their view, the universe is just one big machine.

Materialism connects the philosophy of mechanism to a religious viewpoint, again in which things have no spiritual foundation. God is dead. Humans reign supreme. We’re free to do whatever we choose to do simply because we can do it.

For the past 100 years and on into the future we have been participating and will continue to participate in this philosophical/religious negative vacuum and we will continue to experience it until the time comes when Jesus’ teachings forever obliterate its influence. When we practice the religion that Jesus taught—the religion of personal spiritual experience—our spirits are gradually becoming liberated, and the advances of science are gradually uncovering true reality. I believe that’s the story The Urantia Book is telling us when it uses this “mechanistic materialism” phrase.

Thanks again for your note, and I hope that this reply has been helpful.