Below you will find two responses of mine to an atheist claiming that we are just our brains. The comments are over at Patheos. Enjoy!
So if we are our brains and we are hostage to our brains, why do you blame Christians for believing the things they believe? In your system, a person is rational NOT because they "will" to be, but because their brain forces them to be rational.
Now, if you are right, truth has nothing to do with anything. Your corresponding to reality just collapsed into ashes. You don't believe things because they correspond to reality. You believe them because your brain forces you to believe them.
Accidents do NOT imply agency in the world of philosophy. Accident is any non-essential thing belonging to x. Since all x's are the result of natural processes and chance, then all x's are just accidents of nature. If that is true, no living being possesses any intrinsic value whatsoever. And if that is true, life as we know it is truly meaningless in every sense of the term.
If your brain is in control of your beliefs, then you cannot willingly change your beliefs. How can you know or trust that your brain is after the truth? How can you know or trust that your brain's aim is to function rationally? It would seem to me that in your system, your brain would be after survival, not rationality. And in that case, you really wouldn't be able to trust that your brain was functioning in a way that was even interested in some truth that supposedly corresponds to reality. Instead, it is going to believe whatever it needs to believe in order to survive. And this means that your brain cannot be trusted to deliver on your claim that you are after truth. The reason you believe that all human beliefs require a certain kind of evidence, empirical evidence, is because your brain thinks it is the key to survival, not because it thinks it is true. In fact, everything you think you know could be a lie but it doesn't matter in your brain. All that matters is the substance of what think you know is, in your brain's mind, what you need to think you know in order to survive.
In other words, your brain will function to cause you to embrace irrational views if your brain considers those views necessary to your survival.
Conclusion: since you cannot trust your brain to give you real knowledge concerning reality, your claims to possess knowledge are completely unreliable. Since your brain is more interested in survival than truth, it cannot be considered a reliable source of rationality.
The truth is that you do not live anything like your claims would indicate. Everything you said in your last comment is a glaring contradiction to everything else you have said previously. There is no reason for anyone to listen to anything you say about knowledge or truth or what people ought or ought NOT to believe. We are all surviving just like you and if your right about the human brain, that's all that matters. We can all go home now because nothing anyone says about truth, morality, meaning, purpose, or anything else matters. Your system has just been reduced to irrationalism.
Final response:
Ok, for those reading, I am going to make this my last response because I am just too busy.
Pud has said we are hostages to our brains. That explanation has been reduced to irrationalism because the brain itself cannot be trusted function in a way that is truth-seeking. Now Pud says that our brains are the products of our environments. But if that is true, then it is true of his brain as well. And now we are going to have to talk about which environment is the normative environment. However, we cannot do that if the brain itself cannot be trusted to judge between which environment is the right environment for producing rational brains.
Pud's argument is this: my brain is the normal brain because it comes from the right environment to produce normal brains and the reason I know "this is truth that corresponds to reality" is because my brain, which is a product of that environment, can be trusted to make that determination.
How does pud know his brain is normal? Because it comes from the right environment. How does pud know his environment is normal? Because his brain told him.
Not only has pud been guilty of obvious contradictions in his system, numerous inconsistencies along the way, but now he has committed the fallacy of the vicious circle in his reasoning. I am not sure how many different ways a person's worldview has to be reduced to absurdity before they give it up, but apparently for pud, it is a lot!
This is another reason why we do not ARGUE people into the Christian faith. Only God can open pud's eyes to the truth of the gospel and work the necessary change in pud's mind to accept the truth of Christ.
In their case the god of this world has blinded the minds of the unbelievers, to keep them from seeing the light of the gospel of the glory of Christ, who is the image of God.
The Holy Bible: English Standard Version (Wheaton: Standard Bible Society, 2016), 2 Co 4:4.