Curiously, if someone claims to have a machine which possesses intelligence and consciousness, how can they prove it? How can you disprove the claim?

We credit other humans with intelligence and consciousness, not because we are sure that they have thoughts and emotions, but because they behave as if they do.

Can we produce a legitimate model of the workings of the human brain? We seem to know that the brain is made up of many neurons which are interconnected. Each individual neuron has a reasonably simple behavior. It is the complex combination of them all that we don't understand.

A comparison:

That is, can we figure out how the human brain works. At basic level, individual neurons are rather simple.

What are the minimum requirements for understanding language?
Must understand vocabulary.
Must understand grammer (syntax)

But we use knowledge far beyond that. There are many potential ambiguities in natural languages, due to:

Certainly cannot just translate words:
"The spirit is willing, but the flesh is weak."
[translated to Russiona equivalent of]
"The vodka is acceptable, but the meat has spoiled."

Besides the issue of interpretting text, you need to convert the sound to the words. But how do you know where one word ends and the next starts? How do you determine the words, which are not always spoken in the identical way?

People use clues such as inflections, context, expectations.

How do you keep track of huge amounts of knowledge and then use it to draw inferences. Keep track of facts; draw inferences.
(The Decker/Hirschfield InferenceEngine)

Keep in mind that human intelligence is tough to beat. (Example from Monty Python)
Here is the HolyGrail logic, as a datafile which you should save to disk, and then load from within the InferenceEngine.