In a Galaxy where there are numerous Earth Like worlds, and FTL Travel is possible but only by a small number of species, possibly only by Humans, perhaps they just happened to get there first. In a similar way to Star Trek, where large FTL ships go forth and look for habitable worlds, they regularly come across intelligent life, in various stages of technological evolution

For argument, lets say the ships have whatever Stealth is required that they can observe these planets and not be noticed. I need a way to classify these species (not in a racist way) based on their technology.

I feel I need more fine tuning then the Kardashev Scale Offers. I can name the scale and have it be 1-100 or however many levels I choose, with level x being the level at which my ship would make contact with the species below, and anything before that being worthwhile research on early development of an intelligent species. my Humans are at Level 10.

  1. Pre-Primitive (not able to use tools of any type)
  2. Primitive stone tools, basically Stone Age)
  3. Able to use surface metal deposits to make tools
  4. Regular use of Metal Tools including mining, however not an industrial Society
  5. Industrial Society, basically after the Industrial Revolution
  6. Internal combustion Engine
  7. Nuclear Capable
  8. Capable of Limited Interplanetary travel and Satellite positioning (Current Modern Day Level)
  9. Capable of transit between planets within own Star System, but not inter system
  10. Capable of interstellar Travel
  11. Capable of Inter Galactic Travel

The Question: I need to know what technological breakthroughs can mark the transition from one stage to another that i'm currently missing in the way that Pre-nuclear and post nuclear does.

I know that several other scales exist similar to the Kardeshev Scale like Information mastery by Carl Sagan, which deals with how much, but all of them are based around the way a civilisation uses power or information, Carl Sagan's comes close to what I want but doesn't quite fit the bill. also a lot of these don't incorporate the more primitive species that my Humans might want to research.

I'm also considering a Morality Level (from a human perspective obviously), along with another for how widespread they are so the scientists would visit a planet because they want to study the Bob species which is rated as something like B-5-T, First being how widespread/numerous the species is, second being Tech Level and third being Morality (or something better as the name)

Some levels such as abolishing Slavery would come under the Morality Scale as they aren't based on Tech/tools.

  • $\begingroup$ all level are not equals : there are lot of years between use of metal and industrial revolution, and only few years between 6 and 7... $\endgroup$
    – Kepotx
    Commented Jul 6, 2018 at 15:22
  • $\begingroup$ @Kepotx, I agree i'm just trying to figure out at what significant Technology to put the various other points on the scale $\endgroup$ Commented Jul 6, 2018 at 15:28
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    $\begingroup$ is it mandatory to be a technology? you could use other thing such as the number of people in the same group: is it a small tribe or is it bigger than Dunbar's number? are there Countries, Empires? those are not technologies per se, but can be used to evalue a civilization $\endgroup$
    – Kepotx
    Commented Jul 6, 2018 at 15:34
  • $\begingroup$ Its three scales mixed together, the numbers part is first, then Tech level then Moral, but doing all three would be too broad a question and i think i've got the other scales sorted, but Tech Level seemed a bit... sparse $\endgroup$ Commented Jul 6, 2018 at 15:39
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    $\begingroup$ Reminds me of the table of uncontacted peoples here. It also lists number, whether they are hostile, and occasionally some notes on the technology level ("hunter-gatherers", "metal tools", ...) as well as language etc. I guess the list indicates also that it is difficult to find universally applicable categories. Also note the various entries "recently massacred". If your FTL travellers are humans, you may want to include a category for this. $\endgroup$
    – 0range
    Commented Jul 6, 2018 at 16:17

5 Answers 5


I see a pattern in your list that we can take advantage of. Let's start by building a list of relevant technology groups. This list could be detailed and miles long, but we're interested in those groups that allow us to easily catagorize the process of development. (If this list reminds you of Sid Meier's Civilization games I wouldn't be surprised. I played them a lot as a kid...)

There are a large number of basic tech groups we could use, but let's use three to demonstrate. (Energy production would be another good one, btw, starting with the discovery of fire and ending, perhaps, with antimater or harvesting solar winds or actually discovering zero-point energy...)

  • Tool building
  • Information processing
  • Transportation

OK, now let's list at least five major breakthroughs in each of those categories up to the present day. (This list is very subjective, people will certainly point out where one tech was more indicative than another. That's cool, leave your comments for the OP's benefit. In the end, the list must be his, not mine.)

There's a lot of web-based info you can draw from to do this. I used this site to put the tool list together quickly. I'm not sure I'd trust the date ranges they're suggesting, but the list is pretty good, and focusing on just one item, the hammer, is reasonably indicative of the supporting tech needed for the advancement.

Not surprisingly, you'll find that the basic technologies (e.g., tools) are replaced by more advanced technologies (e.g., information processing) as critical indicators of advancement as time goes on. In other words, "tools" only defines advancement to a point becuse the technology gets to the point where no matter what was done to advance the development of a tool, it's really just "more of the same," the application of new manufacturing tech to the same old tool. Case in point:


  • The hammerstone(stone age)
  • Handles & Leverage
  • Metal hammer heads
  • Water-powered hammering (fixed in one place)
  • Pneumatic hammering (mobile but tethered)
  • Electric hammering (fully mobile, but still using a hammer head)
  • Magnetic hammering (think "rail gun," literally, no physical hammer head)

Why not "metallurgy?" Because while fundamental to many technologies, the advancements in metallurgy are more difficult to discern than the results in advancements in metallurgy — like a better hammer. It is, in my mind, too imprecise to be useful as an indicator of technological advancement.

Information Processing

  • Vocalization (using voice to express ideas)
  • Cave drawings (using our eyes and fingers to express ideas)
  • Music (using something other than voice to experess ideas)
  • Letters
  • Paper
  • Radio
  • Computers (fixed application)
  • Software (flexible application)
  • Modems (Using sound-not-voice to express ideas more complex than emotion)
  • Networking (leveraged application)
  • Cybernetics (using something other than our eyes and fingers to express ideas)
  • Artificial Intelligence (something not human is finally expressing ideas)


  • Domestication of Animals
  • Shoes
  • The wheel
  • Springs
  • Cams & Gears
  • Steam
  • Combustion
  • Flight
  • Rocketry
  • Magnetic propulsion
  • Gravitic propulsion
  • Sublight propulsion
  • FTL propulsion
  • Artificial wormholes

It's obvious that some of these technologies merge in the timeline with others. We want to select the most indicative (call it "obvious") advancements for ease of catagorization. Thus, merging the lists gives us (remember, this is just one perspective, please don't argue about whether or not I picked "the right indicators."):

  • Vocalization
  • The hammerstone
  • Handles & Leverage
  • The wheel
  • Letters
  • Music
  • Water-powered hammering
  • Steam powered tools
  • Flight
  • Radio
  • Computers
  • Rocketry
  • Networking
  • Cybernetics
  • Magnetic propulsion
  • Artificial Intelligence
  • Gravitic propulsion
  • Sublight propulsion
  • FTL propulsion
  • Artificial wormholes

Some observations

  1. You'll notice that the time between steps gets closer as time moves forward. That's because knowledge advances on an exponential scale. Expressing the difference between you, the advanced observer, and them, someone almost as advanced and almost ready to be observers themselves, should be difficult. This means your scale must either become infinitely fine into the future or you give up precision for convenience.

  2. The future is remarkably difficult to predict. I'm fond of the game (I'm about to reveal my age) "Masters of Orion II." In that game, when you've discovered all the known tech there is, you continue by discovering "future tech 1," "future tech 2," etc. You, the author, are in the enviable position of needing to creatively predict the future. That's wonderful! The very best science fiction creates plausible future details. The British TV show "Doctor Who" is credited for (or at least they lay claim to) predicting remote garage door openers. Do this well, and you'll have readers eating out of your hand.

  • $\begingroup$ metallurgy - a very, very wide period of time? Do you mean that "hammering" is better because the period of time it describing is wider? $\endgroup$
    – Alexander
    Commented Jul 6, 2018 at 17:49
  • $\begingroup$ @Alexander, You brought up a good point and I edited my answer to accomodate. Thanks for your help! $\endgroup$
    – JBH
    Commented Jul 6, 2018 at 18:11
  • $\begingroup$ JBH, this was exactly the help i was looking for, Cheers $\endgroup$ Commented Jul 9, 2018 at 7:58

Plenty of science fiction games have similar concepts. To pick just a few examples, from ancient to new.

  • Traveller was one of the early ones. It went through several editions, with slightly modified TL systems.
  • GURPS is another detailed system.
  • The tech trees in the Civilization computer game series.
  • The Twilight Imperium board game.

When you are picking break points for futuristic tech levels, consider what makes a big difference -- often being shot at, or dodging a missile.

  • More compact or more efficient sublight maneuver engines. An increase in Isp or thrust to mass ratios would make a big difference for space combat.
  • More efficient weapon systems. Say beam weapons go from "good for point defense" to "good against starships" at some point.
  • Artificial gravity and/or acceleration compensation.
  • FTL sensors and communications.

The Morality Levels you mention are iffy because they don't have immediate game effects. Both the United States and the Soviets had good scientists, but in the end the economic potential of the West won. But it was a close call.

You took the abolition of slavery as an example. But slavery in the Hellenistic city-states, the American South, and medieval serfdom were completely different things. Each could be abolished at different points of your fictional species, or even reintroduced.

  • $\begingroup$ You're calling Basic Traveller "ancient"?? +1 anyway, even if you make me feel very old. Seriously, the Twilight Imperium example raises another question - is tech level what can be currently manufactured or what "relic" technology is still in use that may be considered a threat? $\endgroup$ Commented Jul 6, 2018 at 17:28
  • $\begingroup$ @KerrAvon2055, with technology as we have it today, keeping relics operational for any length of time requires the tech level to rebuild it. Consider the Iranian trouble keeping their pre-revolution aircraft flyable. $\endgroup$
    – o.m.
    Commented Jul 6, 2018 at 18:21
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    $\begingroup$ +1 for the GURPS mention and @KerrAvon2055, Traveller is ancient (played D&D since 1978). $\endgroup$
    – ShadoCat
    Commented Jul 6, 2018 at 19:04
  • $\begingroup$ I'd like to give you another +1 just for GURPS. Its TL table would suffice for the OP. $\endgroup$ Commented Jul 6, 2018 at 20:35

In human history, you've got about 2,000 years between your level 4 and level 5. which covers massive leaps forward in technoliogy from ancient Greece to the Renaissance. You'd need to insert at least one classification there somewhere.

And yes, we did evolve socially as well. There were all kinds of slavery throughout history, and don't forget to include the fact that slavery itself was a step forward from the times when you just ran in and murdered everybody. But don't forget, social advances aren't independent from technology. The industrial revolution made slavery obsolete, as it was very dangerous. You could replace a free man at no cost, but you had to buy a new slave.

In The USA, slavery died off in the north because they became industrialized and you needed educated or at least skilled workers, you also had a level of fatalities that would make owning slaves prohibitive.

  • $\begingroup$ Actually, a more effective way of killing slavery in the north is the weather. Slaves didn't do as well in the colder climates (probably partially because they were given inadequate clothing), making them less useful than their cost, other than coach drivers, educated servants (i.e. secretaries), etc. for high-class citizens. $\endgroup$
    – user39548
    Commented Jul 6, 2018 at 15:22
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    $\begingroup$ @Hosch250 It's not that the slaves were less effective because they were cold, but the plantation (cotton, sugar...) that doesn't fit with the climate, so the north was more specialized in industry than farming $\endgroup$
    – Kepotx
    Commented Jul 6, 2018 at 15:26
  • $\begingroup$ I agree, however some of that was the dark ages where most technological improvements were restricted. i'm just trying to figure out what Tech breakthroughs could mark one stage to another, and some of points which go between this massive time gaps would be covered in the other parts of the scale but including them would make this far too broad. hence concentrating on just the Tech $\endgroup$ Commented Jul 6, 2018 at 15:30
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    $\begingroup$ @Hosch250 factories were dangerous. You didn't want to risk your slave in a factory, in a mine, or on the railroad. It didn't matter if an Irishman you hired died, you just got another, a slave you had to pay for. $\endgroup$
    – user20762
    Commented Jul 6, 2018 at 15:51
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    $\begingroup$ @Hosch250, that's one of those explanations that sounds somewhat reasonable but no, it isn't. In colonial times, up to a quarter of New York's workers were slaves. If weather was the issue, that wouldn't be the case. As for work in factories, there's another issue, as the Nazis discovered; a slave who wants to screw up on purpose can't do a whole lot to a farm (barring setting a fire or something), and if they do it, are only likely to get away with it once. A slave wanting to sabotage a factory? A lot easier, and greater impact. $\endgroup$ Commented Jul 6, 2018 at 16:05

Since we are talking about aliens we can't expect the same history's "linearity" that's written on our books, therefore i wouldn't go with a one-dimension scale because it can't label a civ as a whole. Multi-dimensional scale, with at least two dimension (morality and energy control).

I'm thinking about something similar to the Internal Protection Code, which indicate the device protection level respect to water and dust, wich are indipendent agents.

I'd write down less than ten level for both moral/civil and energy/science milestone, and then create a codex where "zero" is amoral and pre-tool level and "ten" is galactic peace and interstellar teleport. Therefore you can use description like:

  • "Civ23": slightly better than "animals", but with iron age tools (don't ask me how is it possible, they are alien for some reason!)
  • "Civ47": they cooperate obeying a strong leader/dictator, they can travel to other planet in their own system. (Like Starcraft's Zerg but with less technology)
  • "Civ08": amoral civ made by ipertechnological A.I. with the only purpose to harvest as many energy as they can. (Like WH 40K Necrons, then without Space Marines we are fuck3d...)
  • "Civ99": civ made by interstellar teleporting, illuminated, peaceful tibetan cyber monks (i'd really like to meet one of this guy :) )

I think that these examples are enough to clarify the concept of multi dimensional scale, you could also add another dimension like "probable impact on other civ" or whatever.

You can also get ideas from the RAL scale, it's one of the easiest yet effective way we found to comunicate something as subjective as a color, then a similar concept could be used to indicate a civilization type.

Edit, @Blade Wraith: Other answers offer some examples of "tech trees" but i wouldn't use our tech milestones to define other races' milestones. I doubt that an alien queen would ever try to develop tools, from the basic hammer to the a nuclear device, then "Alien" civ should be a near zero civ on the tech scale. But this doesn't mean that she can't conquer the home planet of a lvl 8 civ (current humans on your list), and how is it possible that a near to zero civ could outperform a 8+ civ, moreover starting the "planet assault" really outnumbered (1 or few VS 7 billions)??? This example shows how this kind of scale can't really define a civ's tech power, it could be used only to compare civs that look almost like us.

The Kardashev scale is based on the energy level rather than the tech level because different civs could use different techs for the same goal, and the really difference is how many energy they can invest to reach the goal. If the Kardashev scale isn't detailed enough it could be improved, but i'd stick with energy levels. Since you are also using a Numerousness indication, i'd go with watt availability of the civ's most powerful entity. You can range from fractions of watt of the unicellular organism to the 10^25W "star eater" level (from here i've estimated the total watts theoretically available to something that can assimilate our sun as 3,6x10^26 W. After that i've realized how dumb i've been because this calculation is the theoretical equivalent of the Dyson sphere, which is quite famous and already calculated). On a second tought the scale could begin at 100W or 1KW, since anything below isn't that interesting, it's good to know that the "civ" exists but nothing more.

You can divide the whole range of interest (10^3 - 10^30 W) in steps and, for instance, have this kind of scale:

  • 1: from 10^3 to 10^5 W
  • 2: from 10^5 to 10^7 W
  • 3: from 10^7 to 10^9 W
  • etc...

To give some hint about the different power level you can add examples of some know entities that fit in the different level, but these entities should be introduced as examples and not as milestones. For instance you can put these examples:

  • 1: from 10^3 to 10^5 W - Roman war chariot
  • 2: from 10^5 to 10^7 W - Supermarine Spitfire
  • 3: from 10^7 to 10^9 W - Nimiz class aircarrier
  • 4: from 10^9 to 10^11 W - fiction...
  • ...
  • 12: from 10^25 to 10^27 W - Death star

Unfortunately this scale (imho) works better but i have to admit that's not really funny to use...

  • $\begingroup$ How would civilizations like Star Trek's Borg fit into this scale? $\endgroup$
    – Alexander
    Commented Jul 6, 2018 at 16:55
  • $\begingroup$ Thats the sort of think i'm going for, but i have Numerousness - Tech level - Moral/Social, as this would allow a civilisation that has spread around their system a bit to have respective codes on the scale. this question is only for the Tech levels, as i need to know the best Technology that marks a transition from one "era" (for lack of a better word) to another $\endgroup$ Commented Jul 7, 2018 at 11:59
  • $\begingroup$ @Alexander: I'm not a ST expert but i guess that Borgs would be a "civ49", a civ with a morality and a social structure similar to the zerg's ones (hive mind, obsessive goal, zero empathy), but with leading edge technology. $\endgroup$
    – theGarz
    Commented Jul 9, 2018 at 7:26
  • $\begingroup$ @BladeWraith: replied in answer. $\endgroup$
    – theGarz
    Commented Jul 9, 2018 at 7:43

Kardashev (<- Spellcheck suggests "correction" to "Kardashian", civilization is doomed.) or Sagan scales are based on laws of thermodynamics and basic properties of life. As such they can be safely assumed to be directly applicable to all civilizations and forms of life, organic or inorganic, sentient or not. They also give a single number that is directly, meaningfully, and accurately comparable between civilizations and forms of life.

Additionally these scales give a real number. There are no jumps or discontinuities. The value is 4.25 ± 0.01, not "maybe 4 or 5, depending on how you regard the copper mining technology in Kingdom of Chalice".

So a civilization looking for a universal scale would still use the Kardashev (easier to do from orbit than Sagan) scale and just expand it to handle the specific needs they have.

An obvious expansion is to also measure the density distribution of energy. Wonders of statistics would give all kinds of fun stuff from this and the peak values, sustained and transient, civilization achieves would give a valuable and universally comparable "just a number".

An example: If a civilization achieves a peak transient energy density comparable to a nuclear weapon, whether it was produced by an actual nuke and whether the locals ever considered weaponizing it, they have the potential to attack anything vulnerable to nuclear weapons.

But more importantly, if your civilization needs more accuracy (as they would) they would use separate data specifically targeted for special needs. No single datum can serve all such needs and trying would only lead to disastrous and preventable errors.

The likely solution would be simply to define a large number of generic protocols for tasks you do in contact with the aliens and then use those as classifications instead of trying to classify the actual aliens. The aliens are under no obligation to fit your neat categories or levels, survey service personnel is. This also gives all the data people actually need (if the protocols are correctly designed and selected) without incomplete, misleading or useless noise.

So instead of telling the expedition the aliens have space ships of level 12 (except see link for the details of propulsion and this link for details on weapons), they would be told that survey fleet protocol Charlie Able with options Gamma and X-ray is active, please read the detailed analysis if you have time, summary even if you do not. Same with social protocols and such.

You could still categorize the aliens based on which protocols are active for them, but it would be based on actual categories with concrete meanings and exact definitions, not on trying to categorize things that never actually exactly match your neat abstract definitions.

You'd want to give them personal digital assistants to remember which protocols are active and what they mean probably integrated into a personal communicator so protocols can be changed on the fly.

Additionally the bureaucracy involved in developing and assigning these protocols has good comedy or parody potential... Imagine being on an alien planet when your PDA tells that first contact protocol X-ray X-ray is now in effect and finding the protocol has two items: "Send your final messages and update your last will" and "Activate the self-destruct on your suit on full sterilize setting and remote trigger. REMAIN SUITED AT ALL TIMES.".


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