Spinoza begins the Ethics by arguing that at the most basic ontological level, the universe is a single, unique, infinite, eternal, necessary existing substance. This is what is most real, and he calls it "God or Nature". Spinoza's God is not some transcendent, supernatural being. He -- or rather, It -- is not endowed with the psychological or moral characteristics traditionally attributed to God by many western religions. Spinoza's God does not command, judge, or make covenants. Understanding, will, goodness, wisdom, and justice form no part of God's essence. In Spinoza's philosophy, in other words, God is not the providential, awe-inspiring deity of Abraham. Rather, God just is the fundamental, eternal, infinite substance of reality and the first cause of all things.One of the advantages I have over readers of this blog is that I get to read Scott's writings long before you do! In three posts than begin on May 1, Scott muses about the congruencies between philosophical Taoism and Spinoza's formulations. He mentions a particular book on the topic and, since I share an interest in the thought of Spinoza, I decided to see if this book is available from my local library system.
~ from A Book Forged in Hell: Spinoza's Scandalous Treatise and the Birth of the Secular Age by Steven Nadler ~
As it turns out, the book Scott references is not available, but the book I quoted from above is and, needless to say, that's the one I checked out. ;-)
From a personal standpoint, I do not use the word "God" in any of my writings simply because of its connotation with religion, particularly Christianity and Judaism. It would lead to confusion to utilize such a common word when I mean it in such an uncommon sense. It is far easier to reference Tao/Dao because most westerners do not have preconceived notions of it. That said, I certainly agree with Spinoza's use of the word, except that I wouldn't go as far as Nadler's description of this first cause as an "it."
In the end, I don't think it matters that much how we choose to designate this underlying first cause or essence. God works just as well as Tao and both work just as well as another word Spinoza utilizes interchangeably, Nature.