A great question related to this is whether a robot is considered life. The scientific community looks for six characteristics of life which are explained here:
Robots actually have shown to present all but #1. How long before nanomachines fill that role? However, the other five, in one way or another have been performed by autonomous robots. When do we draw the line between life and machine?
It's a very good point, but I wonder how many of these characteristics have been fulfilled by any single robot. The link in the comment describes 6 characteristics of life, but I think this list is incomplete. Cells, and organization are effectively the same thing, leaving 3 additional characteristics. Wikipedia has a more complete list of the characteristics of life:
- Homeostasis: Regulation of the internal environment to maintain a constant state; for example, sweating to reduce temperature.
- Organization: Being composed of one or more cells, which are the basic units of life.
- Metabolism: Consumption of energy by converting nonliving material into cellular components (anabolism) and decomposing organic matter (catabolism). Living things require energy to maintain internal organization (homeostasis) and to produce the other phenomena associated with life.
- Growth: Maintenance of a higher rate of synthesis than catalysis. A growing organism increases in size in all of its parts, rather than simply accumulating matter. The particular species begins to multiply and expand as the evolution continues to flourish.
- Adaptation: The ability to change over a period of time in response to the environment. This ability is fundamental to the process of evolution and is determined by the organism's heredity as well as the composition of metabolized substances, and external factors present.
- Response to stimuli: A response can take many forms, from the contraction of a unicellular organism when touched to complex reactions involving all the senses of higher animals. A response is often expressed by motion, for example, the leaves of a plant turning toward the sun or an animal chasing its prey.
- Reproduction: The ability to produce new organisms. Reproduction can be the division of one cell to form two new cells. Usually the term is applied to the production of a new individual (either asexually, from a single parent organism, or sexually, from at least two differing parent organisms), although strictly speaking it also describes the production of new cells in the process of growth.
I think a robot could potentially possess any one of these characteristics, but as far as I know, none have been made that exhibit them all.
Here's a list of ways a given robot could satisfy each characteristic. Perhaps when this list is complete, I could set out to produce a 'living' robot. I'm not sure how it would be accepted, or about the ethics, but it's certainly an interesting idea.
All robots have a certain degree of homeostasis. For example:
- Heat sinks to reduce temperature
- Automatically finding and attaching to a charger to maintain battery charge
- Liquid based cooling systems like those found in cars, and high end computers
Mechanical/Electrical things are inherently grouped by function. The word 'cell' would need clarification.
This is one of the easy ones, I've never seen a robot that doesn't consume energy. We'd have to be somewhat lax on the converting matter into cellular components, unless you consider a battery to be a cellular component. I think the emphasis here is on energy consumption though.
Growth is tough. Is the process of building a robot considered to be a period of growth? Would a robot that builds, attaches/replaces parts of itself in order to get larger really growing? I'm not sure, but it seems this would be very difficult to accomplish without nano-technology.
Robots can be easily programmed to adapt to their environment. This includes adapting their behavior and form. Also, if robots were reproducing, evolution could take place in the same way it does in traditionally living organisms; glitches, or corruptions of the robot's programming would happen randomly and occasionally these 'mutations' would lead to a more fit robot.
Response to Stimuli
Nearly all robots possess this characteristic already, and it is easily accomplished with a wide array of sensors, and microprocessors.
If building another robot is considered reproduction then this is fairly easily satisfied. The parent robot would just gather all the supplies needed and build a copy of itself. I don't think it'd be that hard to make a robot that is specialized in building a copy of itself, especially if you keep the design simple.
I'd say growth and reproduction are the hardest ones to achieve in a bot possessing all the other characteristics. Building a bot that does the other 5 things makes reproduction much more difficult, and growth is just hard all on it's own. We'd have to determine what exactly it is that constitutes growth as well.
Here's the next task: Find a robot that can achieve each one of these characteristics and post the links!
Then we can work on making a single bot do all seven.