Hi Coin,
Personally I would define a computer as a mechanism which an be configured so as to solve generalized problems.
This sounds like a relatively common sense definition of the term “computer”. Thanks for the response.
Now consider that this common sense computer is a device which has at its heart, numerous switches with wires between them. The modern computer is a form of this, with each switch position being driven by some electrical voltage. The switch position is a ‘symbol’ in that it does not represent anything intrinsic to physics. It does not equate to the temperature of the sun for example, nor does it equate to how much money is in your savings account. In order for the switch position to have some equivalent meaning in the real world, humans must assign meaning to these positions. We do that by creating a machine which has a symbol interface such as a monitor with squiggles on the screen which represent something to us depending on our language or other assignment such as the colors used to represent temperature of a model of the sun or the numbers representing dollars or yen in our bank account for example.
Searle, among others, points this out when he says, “… computation is defined syntactically in terms of symbol manipulation. But syntax and symbols are not defined in terms of physics. Though symbol tokens are always physical tokens, “symbol” and “same symbol” are not defined in terms of physical features. Syntax, in short, is not intrinsic to physics.”
(Ref: Searle, “Is the Brain a Digital Computer?”)
If you had a computer terminal into which you typed the question, “What is 12 times 23?” and it came back with 276, you might say this machine was computing something. If it came back with 0110 1011, you might recognize this as being the binomial answer (I didn’t try to actually put the right number in, so use your imagination) and you’d say yes, that’s the same as 276 so it must have computed the answer. Or it might come back with @1U)> in which case, you might pull out your trusty Batman decoder and find that @1U)> equates to 276 and again you’d find this machine was computing something.
The problem we have with defining a computer is exactly this – everything is ‘computing’ something, because everything can be seen to interact to input, and provide output, due to its causal structure. Everything has a causal structure which is governed by physical laws, so what something does can be termed a computer if you’d like.
Again from Searle: “It follows that you could not discover that the brain or anything else was intrinsically a digital computer, although you could assign a computational interpretation to it as you could to anything else. The point is not that the claim “The brain is a digital computer” is false. Rather, it does not get up to that level of falsehood. It does not have a clear sense.”
I’m inclined to agree with that. Being an engineer for 20 years, I look at nature having causal structure that can be broken up into local, independent elements (ex: such as FEA commonly uses). And these elements interact in a way which is clearly determined by local interactions just like a computer. However, it is unclear how we can define one part of nature as being a computer and another part as not being a computer. It simply doesn’t make sense.