&gt; In summary, we&#x27;re looking for ANCIENT Type III civilizations.<p>Yes. This is because of the low probability that intelligent life develops somewhere else at even close to the same time as it did on Earth.<p>Our best understanding is that life has existed on Earth for something like 4 billion years, and complex life has existed for about 500 million. However, complex life capable of building spacecraft (or even radios) has only existed for a few hundred thousand (that is being extremely generous, of course), and only developed that technology in the last ~100 years.<p>If intelligent life has or will evolve somewhere else in the universe, and progresses anything like it did here, then the odds seem overwhelmingly in favour of one of two scenarios:<p>- It evolved millions of years ago, and if it has not wiped itself out, is virtually god-like by our standards due to its head start on technological development.<p>- It has not yet evolved, or at best is the equivalent of primates or the proto-humans of several hundred thousand years ago.