The question is asked “does Spinoza successfully establish that the human mind is identical to the human body?” The predominant view held by the person on the street is of a kind of dualism, of a spirit inhabiting the body, or embodied souls. The problems of such a view, while not the topic of this paper, constitute the objections to the question put before us. I will therefore attempt to illustrate how Spinoza does indeed establish that the mind and body are one and the same as though I were discussing it with a person not familiar with either Spinoza or any matters of philosophy using as ordinary language as I can.
What is it that is you? Of what do you assign your identity, who you are? Some people have told me it is things like character traits, behavior patterns, likes and dislikes, interests and so forth. Yet what of the person to whom some sort of defect has occurred within their brain that utterly changes their personality? What of the debilitating effects of Alzheimer’s disease and other dementia disorders which rob the person of zer memory? Others will assert that our identity is these things plus our various goals and social bonds. The answer to this question won’t be answered here, however I will take that all of these things help to make up one’s identity (and that one’s identity can and does change over time).
The question now is what is it that is essentially you? In other words, when the individual aspects that make up your identity are stripped away, what is it that you are made of? Of what are we humans all alike in? It is here that a common answer given in return is that we are souls inhabiting bodies. Whatever this soul stuff is, the immortality of such is readily believed by many people today. Such souls are believed to be the true minds of what we are. Yet when someone experiences a stroke robbing them of brain function and altering their behavior from kind and gentle to mean and malicious, it is believed by some that the soul is intact but that the body is damaged. After all, they say, a good captain is still hard pressed to navigate a broken ship. The specifics of how an immaterial soul might interact with a material body, though difficult to reconcile, are beyond the concerns of most. Having an eternal soul is a comforting thought.
But let us look at the bare bones of what we can say about ourselves. We take up space. The fancy word for this is extension but think of it as matter, as something material, physical and it can be quite large (like an elephant or a planet) or something quite small (like an atom). There is essentially something physical about you that you share with everything in the entire universe that is made of matter. Okay, so far so good. However there is still this notion of our minds, of the thinking things, our thoughts and souls.
To answer the thinking side of what we are I will need to back up a bit. Spinoza lays out a framework of how the universe and reality is. While ze used the term ‘God’ but to better understand what ze meant we shall substitute All and to avoid ascribing personality characteristics to Spinoza’s use of the word. What is meant by All is literally everything. The All is infinite and is comprised of all things, in all ways, at all times. There can be absolutely nothing that is not a part of this All. If something was not a part of the All then the All would not be everything. Not only is the All literally everything but it is also every possibility. This also means that it is all the ways that things might be or not be. Spinoza wrote of Nature Created and also of Nature Creating, the ways and whys behind the scenes forming the universe around us (of which we are a part). A simple analogy is a billiard table with balls upon it. Suppose the table and balls were the universe. The manners in which the balls scatter and the whys of cause and effect when struck are also part of that universe.
Now let’s go back to the human body for a moment. Has your body always been here? Will it persist forever from now on? Likely your answer is no, at least to the first question. Your body hasn’t always been here. From this we can see that, for your body, existence is not an essential part. What I mean here is not that your body does not exist, for you are existing right now, but that when one puts existence on the table it doesn’t automatically and without question bring up your body. If it did then there would not have been a time when your body was not. However physical matter is something that is an essential part of existence. How can there be existence and there not be anything at all? The key here is that matter (extension) has always been and will always be. This is one attribute of the All, of which your body is one finite part of the infinity of everything.
Now we shall move to the mind. When I say mind it is generally understood by people to mean our thoughts, conscious or otherwise. There is more to the notion of the attribute of thought in Spinoza’s substance (another word for the All) but for this paper we’ll stick to this understanding of the term. Now, recalling our earlier questions about identity, is the essence of thought a part of the essential characteristic of your being? It’s hard not to see how it couldn’t be, for would there be a you without any thought whatsoever? Yet have your thoughts always been in existence? It could be that when we die our thoughts (our souls, as some say) continue on in afterlife. Again, this is very comforting though it isn’t known exactly what happens after death. But besides this, was there a time before your thoughts? Before you were born? While your individual thoughts, your identity, have arisen, come to be, been created in the universe at a definite point of time, the attribute of thought (the bare bones definition of such as a mental thing) has always been as an attribute of the All.
Now to tie the two together, every thought has a physical body. That should have taken you aback. I don’t really mean to say exactly what the statement literally means, that thoughts are physical things floating around in the universe. This is not the case because the two attributes, thoughts and matter (thought and extension) seem separate from each other and it would make no sense for us to say one is the same as other. It is this dualism of difference that many cannot get over to begin with. Yet both are part of the All and while they appear quite distinct from each other there must be a connection somewhere for the two to join up. Why? Consider if they did not join up at some level, they would be completely separate from each other.
With this in mind, bring back the earlier notion that the All is all things and all ways for infinity eternally. Does it make sense to think of either matter or thought being separate from the entire infinite universe of reality of always and forever? Can you be two separate beings, one mental and one physical, at the same time?
In a round-about way we’ve looked at a way that our minds and bodies are one and the same thing. We are finite beings, of a physical and mental nature, that is part of everything at a definite point of time that is but one point in eternity. Take the big picture of an eternal everything as the All, God, or Substance as suits you. Yet Spinoza was, I believe, quite correct in that the best way to understand who and what we are, we must start with the foundations of reality. Starting with knowledge about our own selves and trying to work the other way around gives us the problem of duality, a problem to which I find it much more difficult to arrive at an answer to explain.
 This Ze (nominative), Zer )possessive), and Mer (accusative) are gender neutral pronouns gaining increasing usage throughout various disciplines.
 The well-known case-study Phineas Gage, for example.
 Use of the word ‘God’ is preferable for me; however some people cannot get over the notion of a personable, human like deity. Such a personable concept is shortcoming for such a form is not all things at all times.
 I know this is redundant in saying always and forever and so on. Yet we are told to write this for a specific type of audience and in this I imagine writing it for someone who disdains all talk of philosophy as a waste of time.