We all know the main characteristics of a living thing. Can we ever expect all such characteristics in a robot also? IMHO, it would be impossible. Its body would always be made up of non-cells. If it is made up of cells, it would never be a robot. So in its micro-level it has no life at all. Since it has no life in micro-level we can never say, 'this robot is alive'. But since its functioning resembles a living thing we are compelled to think so.
Let us suppose: 'To feel like a living thing someday perhaps scientists would give life to some of its parts.' Even then we can't say it is alive. We can only say that some inner part is alive. We should not forget that this is not the case of living things. Almost all their cells are alive. So we can always say the thing itself is alive.
But the word 'alive' has another meaning -- alert and active. In that sense only we could say that 'this robot is alive' (if it is switched on and is working. No matter whether its functioning wrongly or not).
Even if we install AI on a robot very effectively, it will only respond as programmed. We can't expect any innovation from it. Any way, if it can perceive our feelings even by an entirely different means, we could say that it is sentient. But it will never have life even in a slightest amount. So, if we are compelled to say that it has life, we would also be compelled to introduce a new biology with weird/new fundamentals.
Let us think about its thinking process.
Though the initial process (analysis) for its working is not thinking as we usually refer, my opinion is that we could say that it is thinking. I didn't forget the fact that the thoughts of a living thing affect each of its cell minutely at least. But here, in the case of a robot, thinking does not affect so. So we should say even though it is thinking, the two thinking processes are entirely different.
Even the same thought is seen in robots of the same type, whereas only similar thoughts can be seen in living things at maximum. This definitely shows that a robot's thought never reaches the level of mind or the subtlest form for thought.
Again, we have already named 'the simulation of human intelligence in machines that are programmed to think like humans and mimic their actions' as AI. More over, this term also refers to any machine that exhibits traits associated with a human mind such as learning and problem-solving. So one could argue: "To exhibit intelligence -- the ability to acquire and apply knowledge and skills, thinking and analysis etc., are necessary. So, also in the case of a robot, we are compelled to use that term -- thinking." We are helpless here. Now that we have already accustomed to this different usage in our day to day life, we can say a robot is thinking (can think) without mind (which is only a bundle of thoughts). Even then don't forget that thinking happens in humans even if nothing is preinstalled deliberately. But this never happens in a robot. So its thinking has not all the things needed for a thinking process.
Your question can be taken mainly in two sense.
- (When these two characteristics are taken separately)
A robot can be considered as 'thinking'; but can't be considered as alive as we usually refer.
I mean, even when we use the term -- 'thinking' IN ALMOST ALL CASES of a robot, we can't say 'it is alive' in future also.
- (When these two characteristics are taken together)
A robot can't be thinking since it can never be alive.
This question has another aspect, but almost all people don't care about that. There, Philosophy of mind 'absorbs' Philosophy of Biology. That situation is mentioned below.
When one realizes what consciousness is, his views about non-living things would change completely. Then the answer to this question would also change. "There is consciousness (also the thing behind thought) everywhere. So there is no difference in living and non-living things.", he would say.