Technical means do not allow detection of alien life

The argument

Possible method of detecting life on an exoplanet: 1. Detection of a sign of life on a planet (such as river, cities, artifacts) requires an image of planet: this would require an impractical optical resolution of a telescope positioned in the Solar System). 2. Sending a probe on an outer solar system is also highly impractical (length of travel). 3. Detection of signals form an alien life is impractical (see also SETI argument)

Context

With current technology we can only prove if a planet is in a habitable zone but not if it can actually harbour intelligent life.

Premises

Counter-arguments

Some missions to our next Solar System can be physically feasible as Breakthrough Starshot According to Kardashev scale level II or III civilisations can be able to harness such high amount of energies that should be detectable on Earth.

Rejecting the premises

[Rejecting P1] Direct imaging of surface features is not how the search proceeds: transit and emission spectroscopy already measure exoplanet atmospheres, and candidate biosignature gases are detectable at that resolution — so the premise sets an unnecessary standard and then concludes from its impossibility. [Rejecting P2] The premise misstates its own case. Probes to the outer solar system have been flown repeatedly, and proposals such as Breakthrough Starshot address interstellar distances with light-sail craft rather than the crewed timescales the premise assumes. [Rejecting P3] Impractical so far is not impossible. SETI has surveyed a small fraction of the sky across a narrow band of frequencies, and a civilisation harnessing energy on the scale the Kardashev classification describes would leave signatures detectable from Earth — so the record is one of incomplete search rather than of a closed door.