Thought Experiment #2
Imagine a super-duper clever machine that can work its way through your brain and, one cell at a time, remove a cell and create a new cell in its place that is physically identical in every way. I know that the brain has a lot of cells but let’s say one cell is replaced every hour and time isn’t an issue (this is, after all, a thought experiment).
When the machine was finished, what would you experience? That you are still there or that you have gradually died?
Or would there be a crucial part of the brain in which you cannot swap even a single cell without destroying what is “you”? If so, where might this be? And would this be remedied by replacing atom-by-atom?
Interesting thought experiments…
(just as an aside, I reckon going from thought to real probably often [always?] reveals aspects of the experiment which we hadn’t ‘thought’ [pun intended] of… Having said that, thought experiments are valuable and I enjoy them)
Interestingly, I’ve heard that every 7-10 years, you are a different (physical) ‘you’ anyway… But yeah, I reckon as long as the ‘super-duper clever machine’ puts things ‘exactly’ back where it found it, you’d still be ‘you’…
Yes, thought experiments have always worried me. They seem to play such an important role in quantum mechanics – which makes me suspicious. Without real input from the reality there is a lot of room for imposing preconceived ideas. I have always found that real experiments almost always thow up aspects one just hasn’t considered beforehand.
That said – I think one would still be there.
Yeah but sometimes they can help to identify a concept that has been phrased incorrectly. Which is what I suspect might be going on when we talk of consciousness. I agree that verifying any notions against reality is important though.
I think thought experiments are helpful for exploring the logic and ramifications of our theories and are helpful in formulating ways to test those theories. In my opinion: the more, the better. The act of testing a theory (that is, the act of running the tests) is only part of the theorist’s job. The theorist first has to determine what he must test in order to demonstrate that his theory cannot be falsified (thought experiments can be a big help here). He also has to know how he will interpret the outcome of the tests once the results are in (they can be a big help here too – they prevent theorists from running inconclusive tests). Thought experiments are just a structured way of thinking – a tool to flesh out theories, and often a way to logically invalidate a theory before going to the time and expense of setting up and running tests. Occasionally, they can even provide inspiration that leads to new theories that were heretofore unimagined. They are in no way a short cut around the rigor of falsification.
I think it’s more than just experiential verification or falsification. In my experience a common feature is that it’s only when the experiment is being carried out that one discovers a flaw in the way it has been designed. Often an experiment becomes a dry run for a more effective or mor powerful experiment. I think the continuous interaction with reality is necessary to design the definitive experiment. That said, I realise my experience has been with easier things. Often these thought experiments are used because there is , as yet, no other way.
I don’t think anyone is denying the importance of being able to eventually ground thought experiments in observable reality. But thought experiments can allow you to creatively examine that may have become a fixed point of view. I’d imagine that it took a thought experiment for early astronomers to have gone from the intuitive view that the sun goes around the earth to the incredible paradigm shift in imagining that it only looks like it goes around us but that we are in fact spinning whilst orbiting the sun. Once this leap has been made it can easily be related back to observable evidence.
Perhaps consciousness is a problem like that of the apparent movement of the sun and stars but a few orders of magnitude more difficult to get our heads around. And that’s why I think thought experiments are probably the only way we’re going to be able to think outside what we intuitively experience. If we just set ourselves experiments we’ll only perform those that we imagine to be useful which may be none if we can’t make that paradigm shift.
That said, there are a number of people who think that if we keep solving the questions around the physical workings of the brain the problem of consciousness will solve itself. Perhaps this will be the case. But I don’t see how thought experiments can hurt just so long as they eventually are grounded in observable evidence (which, Ken, is what I think you are afraid won’t happen).
I think real thought experiments are only used when actual experiments aren’t possible (at least at the current stage of a discipline). There can be thinking about experiments, planning for experiments, etc., which aren’t quite in the same class because it is the actual experiment that counts.
I question whether thought experiments are effective for achieving ‘paradigm shifts’ though. It probably works to some extent in brainstorming situations. But, I think, the greatest initiator of ‘paradigm shifts’ is reality itself. It’s when prevailing theories, thinking, etc., are unable to accommodate the new evidence that we are forced to make these sort of shifts. Perhaps when we can’t obtained evidence from reality we may find it harder to shift out of a popular way of thinking.
It may be unfair of me, but I sometimes wonder if the success of the orthodox quantum mechanical understanding promoted by Bohr resulted from a reliance on thought experiments. In the process some actual experiments have been, at least for a long time, ignored. In effect a (maybe popular at the time) philosophical view prevailed because there was such a preoccupation with thought experiments.