Begin a new game of Heroes of Might and Magic 3 (the best game in the series thus far). Play for a few turns, at least to the point that you have revealed the territory of your AI foes and may observe their movements unhindered by the fog of war. Save the game, end your turn, and note the movements of the AI. Then reload your game, end your turn, and observe once more. The AI will move along precisely the same paths and engage in precisely the same battles that it did previously. It's as though you've rewound a movie and watched the same scene a second time.
Compare this to certain scenes in Half-Life, in which the player may passively observe AI skirmishes between marines and alien forces. The marines may win on one play through, but reload the last save in order to watch the battle again and you will oftentimes find the results to be reversed. No two firefights are exactly alike, even when the same fight is reloaded again and again. The starting positions of the AI entities are the same; the level geometry is no different; the rules governing AI behavior do not change between reloads. So what is it that Half-Life has, and which Heroes 3 lacks?
Put simply, the rules that govern the behavior of Half-Life's AI are probabilistic, whereas those at work in Heroes 3 are deterministic. The distinction is simple, but its implications may help guide us toward a better kind of game -- and maybe even a better kind of worldview altogether.
Physical, or scientific, determinism (hereafter: determinism) is the doctrine which holds that, given knowledge of the position and momentum of every particle in a system at time X, as well as knowledge of the laws that govern the system, a sufficiently powerful mind may calculate the entire past and future behavior of the system as a whole. Determinism reached its popular apex in the eighteenth and nineteenth centuries, after Newton revolutionized the intellectual world with his physics and calculus. But ever since the Einsteinian revolution of the early twentieth century and the subsequent introduction of quantum mechanics, determinism has lost traction in the minds of physicists and philosophers, while yet maintaining some grasp upon the population at large. The movement has its proper roots in the philosophy of the ancient Greek atomist Democritus -- though even earlier mythological entities, such as the Homeric Fates, may serve as evidence that the problem of determinism has weighed heavily upon the Western mind since before the Dark Ages of ca. 1200-800 B.C.
If the determinists are right, and if every single fact in the universe is determined by physical law, then the future is every bit as fixed as the past, and the notion of free will must necessarily evaporate before our desperate eyes. (Although some philosophers believe that determinism is fully compatible with human free will; they are called compatibilists -- or, on occasion, crazy.) That which we call the present can have been produced by only one past, and shall yet produce only one future. Naturally, many philosophers over the years have found this apparent conflict between determinism and human agency most unsettling.
I cannot describe within a reasonable amount of space all of the many attempts that have been made to solve the problem of determinism throughout the ages; nor could I easily do justice to the many subtleties of the arguments, even if I were undaunted by their sheer number. Recently upon reading Charles Sanders Peirce's essay "The Doctrine of Necessity Examined" (P474: The Monist 2 (April 1892):321-27; also CP 6.35-65), however, I was struck by the following paragraph against determinism:
2) By thus admitting pure spontaneity or life as a character of the universe, acting always and everywhere though restrained within narrow bounds by law, producing infinitesimal departures from law continually, and great ones with infinite infrequency, I account for all the variety and diversity in the universe, in the only sense in which the really sui generis and new can be said to be accounted for. The ordinary view has to admit the inexhaustible multitudinous variety of the world, has to admit that its mechanical law cannot account for this in the least, that variety can spring only from spontaneity, and yet denies without any evidence or reason the existence of this spontaneity, or else shoves it back to the beginning of time and supposes it dead ever since. The superior logic of my view appears to me not easily controverted.
I have learned the hard way time and again that Peirce was a really, really smart guy. So whenever I come upon a passage for which I have no frickin' idea what the man's going on about, I try to give him the benefit of the doubt, under the assumption that he's probably worked things out in a manner that has eluded me, and I am simply blind to his superior grasp of reason. Usually, after due time and much effort, I am able to discern the gist of his arguments; but sometimes this is not the case, and I must resign myself to a difference of opinion with my main man Charlie.
When I read the above passage, I initially felt certain that this would be one of those sad times of philosophical disjoint between myself and Peirce. For I could not fathom why Peirce thought that an indeterministic universe would necessarily allow for more variety in the world. Peirce seemed to be saying that a deterministic universe would be one without beauty -- or at least, without a certain important kind of beauty, i.e., that owing to nature's variety and spontaneity. But beautiful variety seemed to me to be accepted as inherent to both the deterministic and indeterministic views of the world; for determinism and indeterminism do not address different worlds as effect, but rather only the supposed contrary causes for the single world that all parties acknowledge we inhabit. It seemed that Peirce was not giving the determinist quite enough credit here.
Then I wondered: is it possible that the determinist and indeterminist do not merely disagree over the supposed cause of the world as we know it, as I initially had thought, but that they also disagree upon the very essence of that world itself? Perhaps they are articulating not merely conflicting world-rules, but also conflicting worlds themselves.
And that's when the analogy to games struck me like a bolt from the blue. For that is exactly the advantage that Half-Life has over Heroes 3: out of spontaneity, variety; out of variety, a kind of beauty. For is it not beautiful (in a sense of the word) to know that each outcome of battle is in some way randomly decided? Who will deny the surge of adrenaline that accompanies the full realization that anything might conceivably happen? Who is not intrigued by the fact that events are not pre-scripted according to some arcane algorithm, but are on the contrary loose and spontaneous? Who would not rather play a game wherein -- all other aspects being equal -- there is an aspect of indeterminacy to the AI?
I now see that Peirce's world is a world in which we may by default justify the delight we feel in studying the history of events, or in predicting their future course. I think that's pretty neat.
What's also neat is the fact that my experience as a computer gamer helped me to interpret this crucial bit of philosophy. Though it was released as long ago as 1998, Half-Life continues to shape me in ways that I cannot anticipate.