Ok, but how is a constructed object and a ... (randomly? naturally? what ever word you want to use) evolved object quantitatively different?
One could follow all the steps involved in getting a human from his evolutionary ancestor to his current state by using a pair of magic tweezers to make each mutation in the genome happen at the right time and in the right way. Could you tell the difference based on the result?
Yes, you can easily tell the difference between entities that have evolved by natural selection, and constructed entities.
(BTW, mutation is random, but evolution is not a random process).
Two example quantitative differences (although, I'm not sure why the specific exclusion of qualitative differences):
1) The human eye, for example, has flaws (that are solved in other similarly evolved eyes) that an engineer laughs at - if you were building a human eye, you wouldn't make the same "mistakes". The deviation from the "better" version is measurable.
2) Evolved entities exist because of procreation. And their only reason for existence is to assist genetic material to replicate. Constructed objects reproduce exactly 0 times and have 0 genetic (or other replicator material).
I think we are arguing at cross purposes here. I'm not arguing what we call evolution doesn't lead to machines very different from the ones that we might chose to engineer ourselves. Rather, I am arguing that, as far as I can tell, I could, given enough time, money and energy, construct a living being using methods very different from natural selection and get the same result. In other words, I don't see why there is anything special about the path taken (some paths may require less energy though. ;-) )
Therefore, I don't consider designing vs evolving as a good way to separate machines capable of consciousness from machines not capable of consciousness.
There is something very special about the path taken (although this phrase is a little misleading) in evolution - not from a design perspective, but from a result perspective - evolution by natural selection is neither a random process, nor a goal-directed design.
Organisms (and by extension, or by reason) are alive because their ancestors have been lucky enough to survive long enough to have offspring.
Note, I'm not arguing that machines cannot be capable of consciousness.
But I am saying that constructed machines are necessarily distinguishable from organisms primarily because they're designed with a goal in mind (unlike organisms - these aren't designed but are the result of the co-operation of genes into higher levels of complexity, team work that has happened to be useful to the survival of the replicating matter - DNA, RNA, or possibly other such material elsewhere in the universe).
I would posit that because of the evolved nature of organisms, there may be flaws in their consciousness (e.g. through chemical imbalance, irrational deduction etc.). It is more likely that machines that are designed for intelligence & consciousness would be gifted (or cursed, depending on your convictions) with perfection, rationality, normalcy, as attributes, or at least their designers would attempt that.
So the the nature of their consciousness would be qualitatively different from that of organisms.
In his 1986 book, The Blind Watchmaker, Dawkins comments:
Any engineer would naturally assume that the photocells would point towards the light, with their wires leading backwards towards the brain. He would laugh at any suggestion that the photocells might point away, from the light, with their wires departing on the side nearest the light.
Yet this is exactly what happens in all vertebrate retinas. Each photocell is, in effect, wired in backwards, with its wire sticking out on the side nearest the light. The wire has to travel over the surface of the retina to a point where it dives through a hole in the retina (the so-called "blind spot") to join the optic nerve.
This means that the light, instead of being granted an unrestricted passage to the photocells, has to pass through a forest of connecting wires, presumably suffering at least some attenuation and distortion (actually, probably not much but, still, it is the principle of the thing that would offend any tidy-minded engineer). I don't know the exact explanation for this strange state of affairs. The relevant period of evolution is so long ago.
You often come across odd stuff like this in machinery. The usual reason is that it made fabrication (or access for repair) easier. Engineering is all about tradeoffs, the "right" design is just one of them.
That's really fascinating--thanks for elaborating.
That said, this isn't, for me, a strong refutation of design. Perhaps the designer's purpose was to create creatures with imperfections such as these, with the higher purpose of communicating something deeper.
Or, is there any way of knowing that we won't some day discover there is a very good reason for this?
An example of something that joubert is referring to is the fact that photoreceptors (rods and cones) in the human eye are actually located behind the retinal ganglial cells, nerve fibers, and capillaries. So light has to pass through a layer of tissue before being detected. One consequence of this is the blind spot.
An engineer would probably try a different ordering.
Evolved entities (read: complex entities) are not designed.