How to think about the claims of advanced technology usage in ancient India?

There's a new form of pseudo-science in India. It involves citing events in mythology to claim that ancient Indians had knowledge of advanced technology of this age like stem cell research, aircraft, plastic surgery etc.

On the face of it, these claims are absurd. Having said that, we have to exercise reason to prove that these claims are absurd. The reasoning can be as follows:

1. Fiction OR Real stories? The first question to ask is - if these mythologies are true stories or just a work of fiction.

Someone can still claim that these stories are real stories. Let's for the sake of argument, assume that these are the real stories. We should then ask the next question.

2. Is there corroborative evidence? In research on history, we do turn to written manuscripts and folk tales to get a sense of the society and people of those ages. It's a legitimate way to find out about our past. But, the events and claims in the stories should have corroborative evidence. Bigger the claim, more the need for corroborative evidence.

For instance, if stories say that people of some age used brass vessels, we should be able to find those vessels in archaeological excavations.

Merely citing a story of the past is not proof enough for the existence of such technologies. It will be similar to a future generation reading our Harry Potter stories and arguing that we have people flying on broomsticks in our age.

We have no corroborative evidence to suggest that these specific technologies existed in the past.

3. Do pre-requisites to such advanced technology exist in the past?: Sometimes we may not be able to find direct evidence of a historical fact, but we can find secondary evidence. For instance, if there is mention of the use of iron tools in India but we do not find iron tools in excavations, we should at least prove that people of those ages knew about iron and how to turn it into tools.

Similarly, if someone's claiming of the presence of advanced technologies in the past, we should ask if the pre-requisites to such technologies existed in the past. For instance, guided missiles, aircraft and test tube babies require metallurgy, electricity (some form of power source big enough to power these), genetics etc. We have no evidence that these pre-requisites existed in the past.

(h/t Aniket Sule)

4. What is the mechanism behind these technologies?: If there is an advanced technology, then there should also be a record of the principles behind it. 

In the case of aircraft, some have quoted ancient texts detailing the technology behind the ancient aircraft. In such cases, we must examine if those follow the laws of physics and if it's feasible to make an aircraft from these principles.

Scientists from IISC Bangalore have examined such texts and proved that it is impossible to make an aircraft from these principles. It is against the laws of physics. 

5Logical consistency: Finally, the claims of the existence of advanced technology in the past should have logical consistency. Some questions that are to be addressed are:

a) If there was technology powerful enough to power aircraft, why use horses and chariots? Why not use some form of cars?

b) If there was knowledge of test tube babies, what are the other instances that it happened?

c) If there is so much knowledge about advanced technologies in ancient texts, why is it that the links are always drawn backwards - using something known in our times to claim that it was known in the past? Why can't something new be made from those ancient texts?

Upon examining the claims using the above five questions, we find that all these claims are ridiculous and absurd! The idea of the post is not just to say that these are absurd claims but also lay out reasons for them being absurd. In future, if someone makes similar claims, they have to address the five pointers above.