The meaning of the proverb is self-evident. We invent what we need; unless we feel the pressure of needs, we are not likely to invent anything. The fable of the thirsty crow which collected pebbles and threw them into the jar to raise the level of water to the bird's reach of lips is well-known.
Mere necessity would not help us much if we are not moved by thought. Animals have their needs but because they lack the power of thinking and ingenuity, they cannot invent anything. They act on instinct and follow a beaten track. Hence, the correct formula should be necessity is the mother of invention but only when it is supported by the power of thinking. This, of course, is obvious. When man feels the pinching need of anything, he begins to think how he can satisfy his needs. He then sets his mind to the task of invention. Necessity gives the first impulse; the rest is the work of the intellect.
In primitive times men lived by hunting. It became necessary to shoot and bring down the bird flying or the beast running beyond the reach of man. Hence, the bow and the arrow were invented. Clothes were devised as protection against cold, houses for shelter. Implements were invented for production of food. In this way, various instruments were made to secure a better standard of living.
Man is not only the slave of his needs but their creator as well. He not only seeks to satisfy his necessity but also his desire for beauty, his lust for power. Culinary skill has been invented to please the palate. Ornaments were invented to add to female beauty. Man has spent millions trying to invent guided locomotives to the moon and other planets like Mars, not because there is any crying need for the same, but because it gives the thrill of doing the outwardly impossible.
The mere satisfaction of needs can never be the sole motive for exercising man's faculties for inventiveness. The proverb tells us not to be passive in our attitude to life,