筈がない
Hardly possible, Cannot be, Highly unlikely, Improbable
Structure
［い］Adjective + はず + が + ない
［な］Adjective + な + はず + が + ない
Noun + の + はず + が + ない
Explanation
Much like はず, which derives from the kanji 筈 and implies something is expected or should logically be true, はずがない is used to express that there is no reason for something to be true. This grammar point conveys strong disbelief and is often translated as 'there is no way that...', 'it can't be that...', or 'it's impossible that...'. In essence, it means that the expectation of (A) being true is completely unfounded.
Because はずがない is a phrase built around the noun 筈, followed by the particles が and ない, it can be attached to any word or phrase that is able to modify a noun.
- 毎日練習したから、試合に負けるはずがない。Since I practiced every day, there's no way I'll lose the match. (It is not expected that I will lose)
- あの店のラーメンはまずいはずがない。It's impossible that the ramen from that shop is bad. (There is no reason to believe that shop's ramen would be bad)
- 彼がそんなに不親切なはずがない。There's no way he is that unkind. (The idea that he is unkind is unfounded)
- これはダイヤモンドのはずがない。This can't possibly be a diamond.
Caution
Pay close attention to the difference in nuance between ないはずだ ('it is expected not to be') and はずがない ('it is not expected to be'). ないはずだ expresses the speaker's logical assumption that the negative is true ('I expect it is not...'). In contrast, はずがない is a much stronger denial of the positive statement ('There is no way it is...').
- この問題は難しくないはずだ。This problem is not supposed to be difficult. (I expect that this problem is not difficult)
- この問題は難しいはずがない。There is no way this problem is difficult. (It is impossible that this problem is difficult)
Examples
あの高い時計が偽物の筈がない。
That expensive watch can't possibly be a fake.
彼はベジタリアンだから、あれは彼のお弁当の筈がない。
He's a vegetarian, so that can't possibly be his lunch box.
水なしで魚が生きる筈がない。
It is impossible for fish to live without water.
あの店は閉まっているから、２４時間のコンビニの筈がない。
That store is closed, so there's no way it's a 24-hour convenience store.
先月フランス語を勉強し始めたばかりだ。映画が理解できる筈がないよ。
I just started studying French last month. There's no way I can understand the movie.
アルバイトだけで、世界一周旅行に行ける筈がない。
With only a part-time job, it's hardly possible to afford a trip around the world.
彼はさっき大盛りを食べたばかりだから、お腹が空いている筈がない。
He just finished a large serving of food, so there's no way he is hungry.
彼女はプロの料理人だから、料理が下手な筈がない。
She's a professional chef, so it's highly unlikely that she is bad at cooking.
本を読むだけでピアノが上手に弾けるようになる筈がない。
It is hardly possible to become good at playing the piano just by reading a book.
彼女は頭がいいけど、この問題を１分で解ける筈がない。
She is smart, but it's improbable that she could solve this problem in one minute.
あんなに正直な彼が、うそをつく筈がない。
An honest person like him would never tell a lie. (Hardly possible)
彼はいつも授業中に寝ていたから、成績が優秀な筈がなかった。
He was always sleeping in class, so it was highly unlikely that his grades were excellent.
チームは誰よりも練習したんだから、今日の試合が負けの筈がない。
Our team practiced more than anyone else, so there's no way today's match will be a loss.