Why is becoming a type 3 from a type 2 civilization the hardest?

I have watched many videos on the topic and still can't figure out why?

Also is there a difference in technology between a type 4 and a type 5 civilization or it is just all type 4 civilizations become type 5 civilizations after some time?

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    $\begingroup$ So far the Kardashev scale is entirely hypothetical. We do not even know of a type I civilization (humanity can hardly be considered a 0.5 when we can not even get that pesky global warming problem under control). So it's entirely hypothetical what it takes to get from one level to another. $\endgroup$
    – Philipp
    Aug 2, 2020 at 20:38
  • $\begingroup$ That's easy.A type 1 civilization can control all the resources of its planet. $\endgroup$ Aug 2, 2020 at 20:45
  • $\begingroup$ @Philipp Somewhere I've read we are on 0.7 . $\endgroup$
    – peterh
    Aug 2, 2020 at 21:26
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    $\begingroup$ There are no "0.7" or "0.75" There is only I, II and III. And they are a model for thinking about advanced civilisation. They don't "exist" we can't say what "usually" or "always" happens. Don't try to make the system a precise measure, it works well as a framework because it is qualitative, not quantitative. A lot depends on whether stable fusion in a power generator is an engineering possibility or not. $\endgroup$
    – James K
    Aug 2, 2020 at 22:40
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    $\begingroup$ The scale is not natural science. There is no way to test it if it fits any observation in nature, not even in thought experiments. I feel I should point that out. $\endgroup$
    – user34599
    Aug 3, 2020 at 0:44

1 Answer 1


No extraterrestrial life has ever been found and we only know of one creature that has formed a civilisation: Homo sapiens. And we have not yet reached type I.

So we know nothing from observations about civilisations that are beyond our own. Kardashev wanted to have a way of thinking that didn't put "humans" at the top, so he described types I, II and III. These give us a way of thinking hypothetically about possible extraterrestrial intelligent life and breaks us free from a human-centred point of view.

Now it might be hard to detect type I or II civilisations, but a type III civilisation would, it seems likely, have profound effects on all worlds in a galaxy or at least the region of a galaxy in which they existed. There does not seem to be any type III civilisation in our part of the galaxy.

Moreover going from type II to type III requires taking over large amounts of star systems and this bumps up against the "space is big" and "you can't go faster than light" problems.

That said, in fact we have no idea if any life form in the whole universe has ever even reached type I

Type 4 and 5 are later additions to the system and there is no standard definition of what type 4 or 5 are (you can extrapolate logarithmically, or you can add some alternate measure of civilisation such as "data processing".

We cannot understand advanced civilizations, we cannot predict their behaviour. Thus, the Kardashev scale may not be relevant or useful for classifying extraterrestrial civilizations.

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    $\begingroup$ James K type 4 civilizations have expanded in the local group of galaxies and type 5 civilizations have expanded even further.My question: Is there a need in advancement of technology from 4 to 5 or all type 4 become type 5 over millions of years? The question can be translated:If we have the technology to reach our local group could we go even further or is it forbidden? $\endgroup$ Aug 2, 2020 at 21:10

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