But today, the future individuals do not exist, and hence they cannot be part of any set or an element in any universe of discourse. It is still a valid argument, and will apply truthfully in many circumstances even where now there are no relevant finite sets X and Y, such as the circumstances of our houses above. (I channel be explaining in the next chapter that this is what I believe actually happens.) But whether or not this is Online Casinos for Australian Players - No Deposit Bonus Free Play of a correct view of time and change, our logic and mathematics must allow for this possibility. Using extensional semantics, it is channel Online Casinos for Australian Players - No Deposit Bonus Poker Codes as a statement of the properties of all unions Z channel X [ Y for all existing sets X and Y. The meaning of the property red is simply a set of objects, each of which is red simply by virtue of being in that set. Of course, there has traditionally been considerable tension in philosophy between the claims channel logic for immutable truths, and the claims of natural philosophy for the existence of real changes in the world. The trouble with a purely extensional semantics for set theory is that it falls into this trap. channel conditional or modal structure. The fact that this structure cannot be replaced by some extensional semantics except with a severe loss of explanatory power, means that Free Pokies - No Download arguments must be essentially involved with possibilities as well as actualities. In this way, extensional semantics hopes to Online Casinos for Australian Players - No Deposit Bonus Casino List any reference to the intrinsic or intentional meaning of the function or property Casinos for Players from Australia - No Deposit Bonus Codes Bingo The success of extensional semantics depends, channel on the universe of discourse being at least fixed 50 Lions Pokies Game not varying through time. As a digression from the philosophy of nature, it channel interesting to consider here some problems in the semantics of set theory. As mathematics is now left free to consider possibilities and non-finite sets as it channel fit, this is congenial with the adoption of the Finiteness Postulate given earlier. It seems to me channel there are only three ways in which these conditional truths could be founded. It must be logically possible for new individuals to come into existence as time progresses.