できるものではない

とはいえ目の前を弾を通りぬけていくなんて、日常生活でそう体験できるものではない。

Hi. I have checked a grammar book and according to it, when ものではない means "it's impossible to do something", we should use た form before ものではない. Why in this sentence is the dictionary form used?

Thank you.

It's not using the past because it's not that grammar. (If it were, I think it would probably be 体験したものではない , but I don't have much experience with that grammar).

The phrase そう体験できるものではない doesn't mean "impossible", it means "Not something you can easily experience."

そう ... ではない is a pattern with a meaning like "not too..." "not very..." ; "not very"+できる⇒unlikely, unusual.
もの is, I think, just an explanatory nominalizer.

There is also a grammar of 動詞＋ものではない that is used to express what shouldn't be ; but I don't think that relates to this sentence.

As Chris-san wrote, it's just そう/そんなに for "not very" in a negative sentence.
e.g.
今日はそう/そんなに寒くない。
彼はそう/そんなに怖い人ではない。
すしはそう/そんなにしょっちゅう食べられるものではない。
富士山はそう/そんなに簡単に登れる山ではない。

zuotengdazuo said:

I have checked a grammar book and according to it, when ものではない means "it's impossible to do something", we should use た form before ものではない.

Click to expand...

That's not just "past form of verbs + ものではない", but "past potential form of verbs + ものではない". For instance, この料理は食べられたものじゃない means "This dish is impossible to eat (= bad taste)", but 食べたものではない can't have this meaning. Plus, the verb must be a volitional verb in this expression, so 体験できたものではない sounds odd.

Thank you both!
I have checked another grammar book. It seems ものではない has a third meaning— "one naturally cannot do something" (please see Notes 1). When ものではない is used in this sense, we can use できる or other verbs in dictionary form before it, as in example (g) and (h). Is it possible that my topic sentence is used in this way?

zuotengdazuo said:

When ものではない is used in this sense, we can use できる or other verbs in dictionary form before it, as in example (g) and (h).

Click to expand...

The verb must be potential form including できる, not just "verbs in dictionary form". 書ける is the potential form of 書く, and 書くものではない doesn't have that meaning.

It seems to me that もの is just a pronoun in the example (g), i.e., 辞書などはそう簡単に書ける本/書物ではない. In fact, 辞書を書くなどというのはそう簡単にできることではない expresses the same meaning. もの is not used necessarily. The example (h) could consider a set expression. もの can't be rephrased with other word.

zuotengdazuo said:

Is it possible that my topic sentence is used in this way?

Click to expand...

日常生活でそう体験できることではない has the same meaning as the original, so I don't think so.