I suspect that the underlying point here is that when EEGs first came around in the 1920s, they were also extremely expensive and not available for common use. But since then, the technologies involved have become so much more accessible and affordable that an electronics hobbyist can build one for themself, maybe even using parts they already have kicking around.
MRIs may very well follow a similar trajectory over time.
Personally, I don't think this will happen in the very near future -- but history shows us time and time again that it's good to start thinking about these things well before they become practical.
That doesn't make sense from a physics perspective.
MRI machines operate by creating intense magnetic fields. In order to create those magnetic fields, you need superconductors, otherwise the magnets would burn up. Thus the liquid helium.
To make this accessible to the hobbyist, you need a revolution in physics, not informatics or engineering. Not saying that it's impossible, but if someone does develop room temperature superconductors, we're going to be talking about a lot more exciting things than handheld MRI machines.
> That doesn't make sense from a physics perspective.
I'm reminded of what a physicist once told me: if a physicist says something is impossible, give up all hope. If a physicist says something is uneconomical/impractical/infeasible, then there is still hope because economics change over time.
> To make this accessible to the hobbyist, you need a revolution in physics, not informatics or engineering.
The big stumbling block in terms of doing this on an (advanced) hobbyist level is the need for liquid helium and rare metals. That's an economic problem, not a physics problem. The helium is a really big deal -- but it's also the one that is most likely to have the economics change in, because the helium shortage is a serious issue and there are lots of people looking into ways to manufacture it efficiently. If they succeed, helium may end up becoming cheap enough to be within the realm of possibility for advanced hobbyists.
Also, the only reason that helium is needed at all is because MRI machines require superconductivity to work. It's not impossible that an advance in that field could happen such that you don't need to make things as cold as liquid helium in order to achieve it.
> we're going to be talking about a lot more exciting things than handheld MRI machines.
Hand-held? Why do they have to be hand-held? I'm just talking about ordinary people being able to build one at all, not how portable it would be.
What are you worried about? That someone will kidnap you, force you into an MRI machine, force you to train it for hours on your neural firing patterns, and get the password to your bank account this way?
I'm trying to figure out which part of this threat model AI makes a meaningful difference in. If they already have you captive, the xkcd-certified $5 wrench is cheaper.
"End of private thought" doesn't seem to be on this tech tree, unless you posit being able to scan people secretly or against their will.
I'm not worried about any of that at all. None of what I've said has some unstated "therefore, this is bad" clause to it. I'm just pondering the progression of technology here.
If someone comes up with a technology that allows people's minds to be read without their cooperation, then I'd start to worry -- but I see nothing in this that indicates that's where things are going.
Also, the idea of building my own MRI appeals to me, so my mind went on a little tangent about how to make that happen.
MRIs may very well follow a similar trajectory over time.
Personally, I don't think this will happen in the very near future -- but history shows us time and time again that it's good to start thinking about these things well before they become practical.