Navneet Bhushan recently asked in TRIZ-journal: "How many new functions mankind has discovered in the TRIZ sense of a function in last 100 years - say 1900 till now?". As most authors and contributors of TRIZ-journal he is unaware of the elementary fact that any new system that implements a new specs thereby implements a new function. New functions in most cases are not discovered but designed.
Mathematically speaking, the set of all possible functions is a forest of trees. Consider, for example, transportation function. This is an abstract function serving as the root of the corresponding tree. Below it are more specific functions such as "land transportation", "sea transportation", "air transportation", "people transportation", "cattle transportation", "molecules transportation", "planets transportation", etc. At this level just one predicate is added. Below these functions are functions with two predicates: "land transportation of people", "transport of electrons in semiconductors", "transport of ions in liquids", "transportation of people through walls", "stars transportation in milky way", etc. The next level of the tree is comprised of functions with 3 predicates, etc. 1
Not all predicates are combinable. Moreover, what is known to be not combinable today may become combinable in the future. For example, "transportation of people through walls" seems to be an impossible combination today. But a future discovery may turn it into a possible combination.
Discovery of the possibility of a new combination can be called discovery of a new function. Discovery of a new root for a new tree can also be called discovery of a new function. But the roots are just verbs (such as move, cut, paint, etc.) and new verbs are rarely needed. Thus, Navneet Bhushan questions should be re-formulated as follows: how many new verbs and applicable attributes combinations were discovered to be possible and implementable in the last 100 years ?
1 It might appear that I erroneously related such functions as "land transportation" and "transportation of people" to the same level on the basis that they both have one verb + one predicate. One could think that transportation should be subdivided into land, air, and sea, which, in their turn, have to be further subdivided into transporation of people by land, transportation of people by air, transporatation of people by sea, etc. But then what is about transportation of electrons ? Can they be transported by land, air or sea ? Of course, we could add to transportation by land, air, and sea also transportation in conductors, semiconductors, and other media and then talk about transportation of electrons in conductors. But it is essentially the same as the above classification of functions into verb, verb + one predicate, verb + 2 predicates, verb + 3 predicates, etc.