I will do my best to explain the concept as follows:
First, let's quickly apply game theory to 4X game...
In game thoery "gameplay strategy" is defined like this:
In 4X, gameplay of a certain player in respect to game theory consists of 3 steps: (simplified version of the original text)Each player in a game faces a choice among two or more possible strategies.
A strategy is a predetermined 'programme of play' that tells what actions to take in response to every possible strategy other players might use.
The above is needed only to understand the meaning of "gameplay strategy" and to recognize that gameplay of a 4X game fundamentally consists of developing an optimal strategy by choosing from a set of possible strategies.1. Assess outcomes or develop a list of possible "gameplay strategies" ordered by the benefit of a strategy
2. Calculate path to outcomes, in the sense of recognizing which sequences of actions are probabilistically associated with which outcomes
3. Select actions from sets of strategies that yield most-preferred outcome, given the actions of the other players.
Next let's define a "fair game":
"Playing correctly" above means to have a winning gameplay strategy, always resulting in victory, which is unfair game.A game which is not biased toward any player.
A game in which a given player can always win by playing correctly is therefore called an unfair game.
A fair game is therefore a game in which there is an equal chance of winning or losing (no winning strategy).
We can say that if a game is fair then the probability of winning is equal to the probability of losing.
An example of a fair game is tossing a coin, the chances of getting heads is equal to the chance of getting tails (50%), there is no "gameplay strategy" which would guarantee only heads or only tails!
This means if you and I toss a coin we both have equal chances of winning, in the long run we win nothing over each other.
An example of unfair game is lottery, because chances of losing are much higher than chances of winning.
This means if you play lottery against lottery organizer then the lottery organizer has higher chances of winning than you, in other words he has a winning "gameplay strategy" which in the long run will earn him more money than yourself.
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Now that we understand what is fair game, what is strategy and how strategies are fundamental part of gameplay it needs to be answered whether 4X game is fair?
Here is an argument of mine (not necessarily correct! just my opinion):
I think it would be incorrect to claim for ex. the AI is getting bonuses and I don’t so the game Is unfair, or likewise I’m intelligent human being and the AI isn’t so the game is unfair.
The reason why I say this is incorrect is because fair\unfair game isn’t about who is "smarter" but rather about having an equal probability to win or lose.
Let’s take for example chess game, chess is fair game since both players have equal chances to win or lose, however both players are not equally skillful nor do they have equal IQ, but this doesn’t make chess an unfair game right?
Also both chess players might play "correctly" (play optimal strategies) but this doesn’t mean both will win, at best they can end up with draw, but they can’t both win no matter how “correct” they play.
There is no winning gameplay strategy in chess.
This is what is meant with "A game in which a given player can always win by playing correctly is therefore called an unfair game".
tossing a coin, chess and lottery are simple examples because you can calculate upfront all possibilities, 4X games are however much more complex and number of possible strategies is bigger than entire galaxy, thus calculation isn't an option, one has to resort to philosophy to get any meaningful result.
For example in 4X game there is a problem with starting position, unlike in chess where both players get equal starting position, in 4X game however you can end up with bad starting position (such as starting at the edge of a galaxy), so we should take stuff like these into account.
I could expand this topic with a lot of additional stuff and examples but now it's up to you to take your position on whether 4X game is fair or not, and then depending on your position how would you defend your position?
You don't have to necessarily agree with my view above, I could be wrong about some things that's why I ask this to see if there is a bug in my reasoning.
Btw. You might have noticed that I'm more interested in single-player game, although multi-player isn't immune to same problem.