I happen to agree that this is likely, but it absolutely is not "clear" that this is the case.
I still wouldn’t argue that this brain in a Petri dish is, in any way, conscious. Despite it sharing the exact same substrate as everyone around me.
[0]: https://www.theguardian.com/games/2026/mar/16/petri-dish-bra...
Leech neurons used to implement a calculator.
Are you suggesting that applications above some level of complexity can't be implemented using biological components? Because I'm pretty sure all I need to show you is a NAND gate in order to prove that arbitrary computation is possible.
Like for example the China Brain - https://en.wikipedia.org/wiki/China_brain. We could in theory organise that and it should in theory be a functional representation of the brain and should in theory prove a functionalist metaphysic of consciousness, just this overlooks the fact that trying to organise that kind of experiment in our reality with a real 1.4 billion people is impractical to the point of impossibility, so in reality it proves nothing.
Or take the hoverboard from back to the future - this seems like a fairly plausible device and is easy to think about, and I could be writing speculative papers about our hoverboard future and what it means for transportation, but when it boils down to it implementing the thing in the way we all believe it should work, like a kind of gravitationally repulsive force field, doesn’t seem like it’s part of physics. I’d want to wait until the day until science delivered an actual good-enough hoverboard that works the same as the one in Back to the Future.
According your definition of empiricism, you wouldn't accept that next years processors will any more powerful than this years until they've been built and you've run a benchmark, which would be a little dumb.
Instead, I'm assuming you combine your knowledge of scaling laws, the basic physics of computation, and your direct observation of the power of modern processors, and infer correctly that next years yet-to-exist machines will be more powerful than those available today.
Re the China brain: its a thought experiment designed to illustrate substrate independence, it is indeed unfortunate that we can't run the experiment. You could absolutely get a small group of individuals together and teach them to reproduce the behaviour of an individual neuron. That would then be enough to demonstrate that a whole brain is possible.
Re the hoverboard: anyone with a basic knowledge of physics knows that this is not possible. Since you have the capacity to reason and access to evidence, you don't have to wait, you can say confidently that it cannot happen unless our physical theories are profoundly wrong.
A basic knowledge of today’s physics would say the hoverboard is not possible. An advanced knowledge of physics five-hundred years hence might show a way of doing it. It “wasn’t possible” to build a thinking, talking machine five hundred years ago and look at us now.
We could make a very dumb biological calculator out of a few genetically-engineered neurons that would very obviously not be conscious.
It's still an open question if we can embed consciousness in our current microchips if we had enough of them together (which I think we currently don't), or if it requires some other physical process we don't fully understand, e.g. quantum. I strongly doubt it does require any quantum shenanigans, but even if it did, we can and will find all sorts of ways to make computers that can perform those shenanigans too. Eventually we're just going to stop being able to move the goalposts, unless you set those goalposts in magic-land.
And say what you want about meat but we don’t seem to find consciousness in rocks or plants or clouds or hairdryers. And the buddists report that some very strange things happen if you meditate for years on end but obviously they must be talking shit and making it up because it’s not testably scientific.