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My Brain Made Me Do It — So What?

By Professor Walter Sinnott-Armstrong

Duke University


Vijeth: Where were you? You promised to drive me to the airport, but you never showed up, and I missed my flight. You haven’t even said sorry. Why did you let me down?

Felipe: I watched a movie instead.  It was a romantic comedy. Don’t be angry with me.

Vijeth: You watched a movie! What kind of excuse is that?

Felipe: It’s the newest kind, a neural excuse.  I really wanted to watch the movie, and my desires are lodged in my brain, so my brain made me do it.

Vijeth: Of course your brain made you do it. It wasn’t your foot or your stomach that made you do it. It was your desires, and your desires are located in your brain; so your brain caused you to do it.

Felipe: Excellent, so we agree.

Vijeth: I agree that your brain made you do it, but that’s irrelevant.  What matters is WHICH PART of your brain made you do it. What made you do it was activations in those parts of your brain that constitute your desire to watch the movie.  That is just a pseudo-scientific way of stating that your desires made you do it.  But if you did it because of the brain states that constitute your desires, then — to put it another way — you did it because you wanted to! And, sorry, that’s still no excuse.

Felipe: You miss my point. My desires MADE me do it. After those desires were in place, given the situation, I HAD to watch the movie.

Vijeth: Maybe I did miss something. Did you struggle against your desires? Did you seriously think about picking me up, but then found yourself somehow overpowered by the appeal of watching the movie? Did the movie distract you so that you simply forgot to pick me up?

Felipe: No, none of that. I just discovered that the movie was on television and decided to watch it.

Vijeth: Then you controlled your actions. If you had not wanted to watch it, you would not have watched it. Nobody and nothing outside you made you do it. Your brain—or at least the part that constitutes your desire to watch the movie—is part of you. It is not some alien invader. It is not like a tumor that grows against your will and can be cut out (see and You have no basis for denying that your desires reflect who you are.

Felipe: But something external created those desires. My parents loved romantic comedies, and passed their passion on to me.  I couldn’t help but want to watch that movie. And, gee, it was good.

Vijeth: Don’t blame your parents. You could still control how you acted.

Felipe: Not really. In the precise circumstances, given all of my desires and beliefs, I would act in the same way every time.

Vijeth: Fine, but one factor in those circumstances is how much you care about me, right?

Felipe: Sure.

Vijeth: And if you had cared more about me, you would have driven me to the airport before watching the movie. So what your excuse comes down to is that your brain did not include enough concern for me. How is that supposed to make me less enraged? Your brain does not care about me or you do not care about me. Either way, you treated me like dirt.

Felipe: Please try to understand. I had no choice about how much I cared for you.  Since my concerns determined my acts, I had no choice about how I acted.

Vijeth: No choice? You had a working car, and you remembered that I was counting on you. If you had chosen to keep your promise, then you would have kept it. So you did what you did because you chose to do that and not something else. If you deny that you had a choice, I don’t know what you mean by a choice.

Felipe: Okay, there was a choice, but I did not make it. My brain did.

Vijeth: Does that even make sense? Anyway, if your brain made the choice, and if the part of your brain that made the choice was the part that constitutes your desires, then that convoluted description just means that you chose to watch the movie because you wanted to watch it and didn’t care enough about me.

Felipe: I grant you that I made a choice. However, I had no real option, because my action was inevitable.

Vijeth: Again, what matters is not THAT it was inevitable but WHAT MAKES IT inevitable. The only things that made your choice inevitable were your desire to watch the movie and your lack of concern for me. It’s not like you were pushed or threatened. What you did depended on your own desires and choices.  Redescribing those mental states in terms of brain states does not change the crucial fact that you chose to watch the movie because you wanted to watch it more than you cared for me. I have every reason to be furious with you.  This is not affected one iota by a pseudo-excuse, like “My brain made me do it”.

Felipe: I’m really sorry.

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3 Comment on this post

  1. Jonathan MS Pearce

    A nice example of the reasonings either way on this.

    On the tumour angle, there is this idea that tumours are negative brain and biological states that put us out of the norm, but this says nothing about the norm being equally valid as a brain state and biological scenario.

    I tried to look at that in the article above, though may in some way be seeing things from a Felipe point of view. That said, I think there is a difference between a fatalistic notion of a brain state, and a corrective understanding of how we would prefer things to bo.

    “Fair enough, Felipe, but if you do that ever again, you can stick our friendship where the sun don’t shine. Stick that input in your computation.”

  2. I agree that Vijeth wins.
    In case Felipe fails to apologize, another potential reply would be:

    Vijeth: Alright, so you insist that you had no choice, your brain made you do it, and that’s that.
    Now, by your own standards, I have no choice! My brain already decided that I blame you and that I shall be mad at you – as evidenced by the fact that I’m doing just that.
    Granted, you might try to influence my brain with your behavior – including words, etc. But regardless of what causes my behavior, thoughts, etc., your attempt is backfiring, because I believe your insistence on the “brain” excuse is unreasonable, and I’m getting increasingly mad at you. Now I not only blame you for your earlier behavior, but also for insisting on that excuse.
    If your points were correct, then similarly, I would have no choice on that, either. Under that assumption, my brain just makes me find your insistence unreasonable, makes me find your rationale fatally flawed, and keeps making me madder.

  3. If we invented a conscious-character-enabled holo-deck and loaded a non-interactive holo-novel of the Star Wars films, then Tarkin will inevitably destroy Leia’s home planet Alderaan. Within the context of the holo-novel – which is deterministic – no other result is possible.

    On playing the holo-novel one time we (in the context of our Universe which we assume to have libertarian free will) decide to pause the holo-novel, set it to LFW-interactive mode (which allows us to interact with the conscious characters and give them LFW) , enter the simulation, and reveal to them their previous existential situation.

    In this scenario, although presumably Tarkin will still feel no remorse (his character having had to have developed that way), should Leia still put the intellectual blame on him? Or does it shift to us? Or perhaps George Lucas? Or no blame at all?


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