The economic actor is assumed to be constantly engaged in rational pursuit of self interest. This is not a realistic model - merely a (useful) approximation. People don't repeat their mistakes systematically (=rationality in economics) and they seek to optimize their preferences (altruism can be such a preference, as well).

Still, many people are non-rational or only nearly rational in certain situations. And definition of "self-interest" as pursuit of fulfilment of preferences is a tautology.

V. Consumer Choices

How are consumer choices influenced by advertising and by pricing? No one seems to have a clear answer. Advertising is both dissemination of information and a signal sent to consumers that a certain product is useful and qualitative (otherwise, why would a manufacturer invest in advertising it)? But experiments show that consumer choices are influenced by more than these elements (for instance, by actual visual exposure to advertising).

VI. Experimental Economics

Von Neumann proved that there is a solution for every ZSG with 2 players, though it might require implementation of mixed strategies (strategies with probabilities attached to every move and outcome). Together with economist Morgenstern, he developed an approach to coalitions (cooperative efforts of one or more players – a coalition of one player is possible). Every coalition has a value – a minimal amount that coalition can secure using solely its own efforts and resources. The function describing this value is super-additive (the value of a coalition which is comprised of two sub-coalitions equals, at least, sum of values of two sub-coalitions). Coalitions can be epiphenomenal: their value can be higher than combined values of their constituents. The amounts paid to players equal value of coalition and each player stands to get an amount no smaller than any amount that he would have made on his own. A set of payments to players, describing division of coalition's value amongst them, is "imputation", a single outcome of a strategy. A strategy is, therefore, dominant, if: (1) each player is getting more under strategy than under any other strategy and (2) players in coalition receive a total payment that does not exceed value of coalition. Rational players are likely to prefer dominant strategy and to enforce it. Thus, solution to an n-players game is a set of imputations. No single imputation in solution must be dominant (=better). They should all lead to equally desirable results. On other hand, all imputations outside solution should be dominated. Some games are without solution (Lucas, 1967).

Auman and Maschler tried to establish what is right payoff to members of a coalition. They went about it by enlarging upon concept of bargaining (threats, bluffs, offers and counter-offers). Every imputation was examined, separately, whether it belongs in solution (=yields highest ranked outcome) or not, regardless of other imputations in solution. But in their theory, every member had right to "object" to inclusion of other members in coalition by suggesting a different, exclusionary, coalition in which members stand to gain a larger payoff. The player about to be excluded can "counter-argue" by demonstrating existence of yet another coalition in which members will get at least as much as in first coalition and in coalition proposed by his adversary, "objector". Each coalition has, at least, one solution.

The Game in GT is an idealized concept. Some of assumptions can – and should be argued against. The number of agents in any game is assumed to be finite and a finite number of steps is mostly incorporated into assumptions. Omissions are not treated as acts (though negative ones). All agents are negligible in their relationship to others (have no discernible influence on them) – yet are influenced by them (their strategies are not – but specific moves that they select – are). The comparison of utilities is not result of any ranking – because no universal ranking is possible. Actually, no ranking common to two or n players is possible (rankings are bound to differ among players). Many of problems are linked to variant of rationality used in GT. It is comprised of a clarity of preferences on behalf of rational agent and relies on people's tendency to converge and cluster around right answer / move. This, however, is only a tendency. Some of time, players select wrong moves. It would have been much wiser to assume that there are no pure strategies, that all of them are mixed. Game Theory would have done well to borrow mathematical techniques from quantum mechanics. For instance: strategies could have been described as wave functions with probability distributions. The same treatment could be accorded to cardinal utility function. Obviously, highest ranking (smallest ordinal) preference should have had biggest probability attached to it – or could be treated as collapse event. But these are more or less known, even trivial, objections. Some of them cannot be overcome. We must idealize world in order to be able to relate to it scientifically at all. The idealization process entails incorporation of gross inaccuracies into model and ignorance of other elements. The surprise is that approximation yields results, which tally closely with reality – in view of its mutilation, affected by model.

There are more serious problems, philosophical in nature.