By David Brin, Richard K. Graf, Alexei Turchin, Philippe Van Nedervelde, and other members of the Lifeboat Foundation Scientific Advisory Board.
 
 
OVERVIEW

As any alien race able to reach us is likely to be considerably more advanced than us, we would do well to develop a communications and diplomatic protocol to minimize any frictions caused by a first contact situation, be it friendly, unfriendly or neutral. In particular, we would discourage actions which could all too easily be misinterpreted as overtly hostile such as preemptively scrambling — let alone launching — nuclear weapons during a possible first contact. The rule when engaging in contact with an alien race is to do anything possible to avoid war since we are quite likely to lose.
 
This program will be devoted to developing the first contact protocol.
 
In addition to this protocol, we should be careful about any devices that we are told to construct via alien messages, as such devices could be unfriendly AI or other harmful devices. If such a danger is suspected, this warning must be immediately made public knowledge to discourage others from activating possible alien weapons.
 
Finally, we are against any efforts to on purposely provide our technological level and location to potentially hostile aliens.
 
 
FIRST CONTACT PROTOCOL

A policy of non-physical contact communications would be a good first start. We should keep a reasonable quarantine distance until a level of trust has been established.
 
 
COMMUNICATION TYPES

Methods of communicating include mathematical languages, pictorial messages, multi-modal messages, and algorithmic messages.
 
 
MATHEMATICAL LANGUAGES
 
An example of a mathematical language is Lincos, published in 1960 by Hans Freudenthal, which created a general purpose language derived from basic math and logic symbols.
 
The Lincos "dictionary", intended to be transmitted first before any additional messages, begins with a simple pattern of pulses intended to establish the terminology for natural numbers and basic arithmetic (addition, subtraction, multiplication and division) in base two. The concepts of equality, comparison, variables and constants are also illustrated by a series of examples, and then finally propositional logic, set theory and first-order logic.
 
The next section of the Lincos dictionary establishes vocabulary for describing time, introducing means for measuring durations, referring to moments in time, and talking about past and future events.
 
The third section is perhaps the most complex, and attempts to convey the concepts and language necessary to describe behavior and conversation between individuals. It uses examples to introduce actors speaking to each other, asking questions, disapproving, quoting other people, knowing and wanting things, promising, and playing.
 
Finally, the fourth section describes the concepts and language relating to mass, space, and motion. This last section goes so far as to describe physical features of human beings and of the Solar system.
 
 
PICTORIAL COMMUNICATION SYSTEMS
 
Pictorial communication systems seek to describe fundamental mathematical or physical concepts via simplified diagrams sent as bitmaps. These messages assume that the recipient has similar visual capabilities (weak assumption) and can understand basic math and geometry (strong assumption because both are prerequisites for building the optimal shape for a radio or optical telescope). A common critique of these systems is that they assume a shared understanding of special shapes, which may not be the case with a species with substantially different vision, and therefore a different way of interpreting visual information.

Colorized version of Arecibo Message

Starting cases include: alien message intelligible and alien message not intelligible.
 
If intelligible, then the answer depends very much on what we believe the message says... which suggests the answer may include a) acknowledgement of receipt of the message; b) what we believe the message to mean; and c) request to confirm that our interpretation is accurate and if not for them to rephrase the message.
 
If not intelligible, then we want to send a message which says (in a variety of ways that we think they might understand, informed by elements from their message) a) acknowledgement of receipt of a message; b) declarations in various forms that we did not understand the message nor any parts of it; and c) request to resend the message, but perhaps in a more complete form, or to send us a different message using elementary logic, mathematics involving universal constants, and an elemental iconic language.
 
As soon as we have any kind of contact which is unintelligible to us, we should send them the modern equivalent of the Rosetta stone: a sample of text translated into most human languages — living languages as well as ancient ones.
 
To establish communication it will be necessary to create a common reference from which further discussions could be conducted. We recommend that a list of "Universal" references be created that could be used to form a basis for further efforts.
 
A demonstration of prime numbers and universal mathematical concepts, such as Pi, Pythagoras and various other mathematical formulas, and then a exchange of simple chemistry would be a good start.
 
There is no reason to necessarily expect that our new "friends" would have evolved in an environment that would have lead them to evolve the abilities to either see or hear in the same frequencies that we do. If the physiology of the aliens is sufficiently different we may not possess the appendages or organs to make easy communications possible.
 
Humans are very visual creatures. Even if there is a language barrier between us we can usually gesture and point and eventually get another human to understand what we are trying to convey. (Galactic charades anyone?) If contact is made physically then one could attempt to use the tried and true finger pointing "Me Tarzan" method of establishing a common reference.
 
 
RESOURCES

Communication with Alien Intelligence by Marvin Minsky.
 
Declaration of Principles Concerning Activities Following the Detection of Extraterrestrial Intelligence, SETI Institute.
 
SETI Hacker? by D. Carrigan.
 
SHOUTING AT THE COSMOS...Or How SETI has Taken a Worrisome Turn Into Dangerous Territory by David Brin - 2006