This is going to dissolve into a flame war with remarkable rapidity.....
Let's look at things logically.
Firstly we must define what 'consciousness' is. The Oxford Compact English Dictionary defines consciousness as:
1) The state of being conscious
2) Awareness, perception
Dropping the first definition as it's irrelevant to the point, we are left with option 2, that of consciousness being defined as awareness and perception.
Feeding that definition seamlessly back into a real-world context, you and I are both aware of our surroundings. For example, I'm sitting here at my computer, and I'm aware that there's a light on in the corner, and that my pet rabbit is scratching away at something in his hutch. As I look around the room, I see things. Percieve them.
Living things, besides some of the more obvious functions that they carry out, all have some element of awareness and perception. A plant is aware of where the sun is and adjusts the position of its leaves throughout the day accordingly. My rabbit, Dandelion, is aware of where he is (in a hutch in the corner) and where his food bowl is, for want of a better example.
Looping back to the original argument, that of a Tamagotchi vs a dog for 'consciousness' we must ask ourselves this: Is a Tamagotchi actually aware of its surroundings? Can it percieve things?
The answer is 'no' in both cases. A Tamagotchi is programmed to react to certain pre-defined stimuli. When playing with a Tamagotchi you have a choice of things to do. IIRC you can feed it, play with it and do a couple of other things. What you can't do is throw a grenade at its feet and see how it would react. The Tamagotchi doesn't have a 'grenade' option in its code.
On the flipside, if you throw a grenade at a dog's feet, it would react in any number of ways. It might run away, it might sniff at it wondering what it is, or indeed it might pick it up in its mouth and return it to you as if it was a stick that you'd thrown. Naturally, we view two of those options as downright stupid, but that's because we know what a grenade is - the poor dog doesn't until it blows up, by which point it wouldn't care anyway.
Consciousness, as I've stated, is a difficult thing to define. Even when you've got the definition from a dictionary you need to interpret it correctly. I suppose it comes down to this:
Consciousness is the attribute that a thing has if it is able to percieve its environment, be aware of what it is and what it is doing, and being able to react to unexpected stimuli. Living things can do that to varying extents, artificial life like a Tamagotchi can't. At least, not yet.
In the original example, Singh's dog was a perfectly happy, healthy and energetic creature who was as much a part of Singh's life as his sibling(s), his parents or his friends. Losing that companion, even though said companion wasn't human, left a large hole in Singh's heart. He could never replace that dog, not even if he managed to find another animal of exactly the same breed, temperament and colouration as the one he's lost. If it had been a Tamagotchi, you'd just reset, hatch the egg and start again. Sure, you might feel a slight sense of loss as you'd worked hard to evolve that Tamagotchi, but it's still technology. You can't pet it, you can't hug it and you sure as hell can't think of it as a companion in any stretch of the imagination.
In my life, I've got a house rabbit as I mentioned earlier. He's about seven years old now, and I'm quietly preparing for the day when it'll all be over. Most rabbits live on average for about eight years, so I doubt I've long left. But I've shared some moments with him, mainly because he's been a close part of my life. He's been 'there' during some of the toughest parts of my life, such as losing my father suddenly nearly two years ago. He's more than just a pet, he's a companion and a friend. Sure, he can't speak to me or play multiplayer F-Zero on my Gamecube, but with him around at least one thing will go right in the day. He'll always be happy to recieve a scratch on the nose or to hop around like a maniac when I waggle his food container in front of him prior to pouring it into the bowl. Although he's a rabbit, with all the lower intelligence that comes with it, sometimes he acts so 'human' it's untrue.
For those of you that have a pet, give it a hug right now. Unless it's a goldfish or a boa constrictor, that might not be a good idea. With them around, our life feels less empty. Your life might suck big time, but it'll suck less if you spend just five minutes with your pet.
That, my friends, is joy.