Even if you can't define the exact point that A becomes not-A, it doesn't follow that there is no distinction between the two. Nor does it follow that we can't know the difference. That's a pretty classic fallacy.
For example, you can't name the exact time that day becomes night, but it doesn't follow that there is no distinction.
A bunch of transistors being switched on and off, no matter how many there are, is no more an example of thinking than a single thermostat being switched on and off. OTOH, if we can't think, then this conversation and everything you're saying and "thinking" is meaningless.
So even without a complete definition of thought, we can see that there is a distinction.
> For example, you can't name the exact time that day becomes night, but it doesn't follow that there is no distinction.
There is actually a very detailed set of definitions of the multiple stages of twilight, including the last one which defines the onset of what everyone would agree is "night".
The fact that a phenomena shows a continuum by some metric does not mean that it is not possible to identify and label points along that continuum and attach meaning to them.
For example, you can't name the exact time that day becomes night, but it doesn't follow that there is no distinction.
A bunch of transistors being switched on and off, no matter how many there are, is no more an example of thinking than a single thermostat being switched on and off. OTOH, if we can't think, then this conversation and everything you're saying and "thinking" is meaningless.
So even without a complete definition of thought, we can see that there is a distinction.