Japanese has a fundamental principle: you can state your own feelings directly, but you can only observe others' feelings from the outside. This rule runs through 思う, たい/たがる, and emotional adjectives + がる as a unified system.
思う: "I Think" vs "He Thinks"
思う has two meanings:
| Meaning | Example |
|---|---|
| Thinking/believing | 私はそう思う。 (I think so.) |
| Feeling | つらいと思う。 (I feel it's tough.) |
The key difference is person:
First Person: Use 思う Directly
When expressing your current thought or feeling, use the plain form:
-
私は女は悪いものだと思わない。 → I don't think women are bad.
-
日本語は難しいと思う。 → I think Japanese is difficult.
Third Person: Must Use 思っている
How do you know what someone else thinks? You've observed it over time -- they've been holding this opinion. So you need ている:
-
兄は女は悪いものだと思っている。 → My brother thinks women are bad. (He's been holding this view)
-
田中さんは来年転職しようと思っている。 → Tanaka is planning to change jobs next year. (He's been thinking about it)
Comparison
| Person | Form | Nuance |
|---|---|---|
| 私は | 〜と思う | My current thought (stating right now) |
| 私は | 〜と思っている | I've been thinking this (ongoing belief) |
| 兄は | 〜と思っている | He thinks... (must use continuous form) |
First person can also use 思っている to mean "I've been thinking this for a while." But third person must use 思っている.
ようと思う vs ようと思っている
Volitional form + と思う means "I intend to do something":
| Form | Nuance |
|---|---|
| 〜ようと思う | Deciding on the spot -- I'm going to do this |
| 〜ようと思っている | Have been thinking about it -- I've been planning to |
-
来年、美術大学を受けようと思う。 → I'm going to take the art university entrance exam next year. (Just decided)
-
来年、美術大学を受けようと思っている。 → I've been planning to take the art university entrance exam next year. (Thought about it for a while)
For third person, only 思っている works: 息子は美術大学を受けようと思っている。
がる: The Third-Person Rule for Emotional Adjectives
This rule is even stricter than 思う. Japanese emotional adjectives (嬉しい, 悲しい, 怖い, etc.) can only directly describe the speaker's own feelings.
Why This Restriction?
The logic: emotions are internal states that only the person themselves can confirm. Other people's emotions can only be inferred from external behavior.
So Japanese invented the suffix がる -- it turns emotional adjectives into verbs meaning "to show signs of being..."
Conjugation Rules
| Type | First Person | Third Person |
|---|---|---|
| い-adjective | 嬉しい | 嬉しがっている |
| な-adjective | 不思議だ | 不思議がっている |
| たい | 食べたい | 食べたがっている |
| 欲しい | 欲しい | 欲しがっている |
Example Comparisons
First person -- use the adjective directly:
-
私はみんなの助けが嬉しい。 → I'm happy about everyone's help.
-
私はこのことが不思議だ。 → I find this mysterious.
Third person -- must use がる:
-
山田さんがみんなの助けを嬉しがっている。 → Yamada seems happy about everyone's help.
-
兄はこのことを不思議がっている。 → My brother finds this mysterious.
Watch the Particle Change
When you add がる, the particle が changes to を:
| Emotional Adjective | がる Form | |
|---|---|---|
| Particle | 〜が嬉しい | 〜を嬉しがっている |
| Reason | が marks the object of emotion | がる is transitive; objects take を |
がる turns adjectives into transitive verbs, so the object switches from が to を.
The Complete System
| Expression | First Person | Third Person |
|---|---|---|
| Thinking/believing | 〜と思う | 〜と思っている |
| Want to do | 〜たい | 〜たがっている |
| Want (a thing) | 欲しい | 欲しがっている |
| Happy | 嬉しい | 嬉しがっている |
| Scared | 怖い | 怖がっている |
| Mysterious | 不思議だ | 不思議がっている |
| Lonely | 寂しい | 寂しがっている |
One consistent logic: state your own feelings directly; observe others' feelings from outside.
Practice
Q1. Fill in: 田中さんは日本に帰ろう＿＿。(Tanaka has been planning to go back to Japan)
A. と思う B. と思っている
Show Answer
B. と思っている. Tanaka is third person, so the continuous form is required. And "has been planning" is inherently ongoing.
Q2. Why can't you say 「兄は嬉しい」?
Show Answer
Because 嬉しい is an emotional adjective that can only describe first-person feelings directly. You can't confirm your brother's feelings -- you can only observe them from outside. The correct form is: 兄は嬉しがっている (My brother seems happy).
Q3. Convert 「私はこのことが不思議だ」 to have Yamada as the subject.
Show Answer
山田さんはこのことを不思議がっている。 Note two changes: the emotional adjective becomes がっている, and the particle changes from が to を.
Summary
- 思う: first person uses it directly; third person must add ている
- ようと思う = deciding now; ようと思っている = have been planning
- Emotional adjectives (嬉しい, 怖い, etc.) only describe first person
- Third person uses the がる suffix, turning adjectives into verbs (external observation)
- がる is transitive, so が changes to を
- Core principle: state your own feelings directly; observe others' from outside