2.2.2 Important Perspectives of Things and Ways of Thinking: Part 2

Full Title: Important Perspectives of Things and Ways of Thinking: Part 2

[Article No. 2.2.2]

日本語タイトル：大切なものの見方・考え方: Part 2 [記事 No. 2.2.2]

Posted on June 14, 2026.

[Images (continued from Part 1)]

(In Japanese)

Source: By Yoshida.

[Discussion]

社会に存在する各経済主体，世界，国・地方政府，企業，NGO，NPO，家計，個人等は，意識的か無意識的かにかかわらず，Image 3 に示す「制約条件付き最適化問題」を適宜解いて政策決定，意思決定を実施している．
上記最適化問題になぜ制約条件が付いているかといえば，各経済主体がコントロールできる制御変数は有限な領域でしか動かせないためである．

* 社会に存在する各経済主体は有限資源の世界で活動しているため，「制約条件付き最適化問題」を解かざるを得ない．

3. こで制約条件付き最適化問題の簡単な例，「予算制約下における個人の効用最大化問題」を示そう．各個人はそれぞれが直面する予算制約下において，自らの効用を高めてくれる各財・サービスの最適消費量（ベクトル）を決定している（この例における制約条件＝予算制約，制御変数＝財・サービスの消費量）．もし，各個人が予算制約に直面していないのであれば，各個人は各財・サービスを無限に消費して，どこまでも自らの効用を高めることができるであろう．しかし，このような想定，すなわち，各個人は予算制約下にないという状況は非現実的であることがおわかりいただけるであろう．

All economic agents in society—including the world, national and local governments, corporations, NGOs, NPOs, households, and individuals—make their policies and other decisions by solving the “constrained optimization problem” illustrated in Image 3, whether consciously or unconsciously.
The reason why constraints are imposed on the optimization problem described above is that the control variables available to each economic agent can only be adjusted within a finite range.

* Since all economic agents in society operate within a world of finite resources, they are compelled to solve “constrained optimization problems.”

3. Here, let us consider a simple example of a constrained optimization problem: the “problem of maximizing individual utility under a budget constraint.” Each individual determines the optimal consumption quantities (vector) of goods and services that will maximize his or her utility, subject to his or her budget constraint (in this example, the constraint is budget, and the control variables are the consumption quantities of goods and services). If individuals were not subject to budget constraints, they could consume each good and service in unlimited quantities and thus increase their utility indefinitely. However, you will likely agree that this assumption—namely, that individuals are not subject to budget constraints—is unrealistic.