Can "man" always be used to mean both men and women?

According to the dictionary, man can refer to both men and women. Take this example:

Understanding the laws of physics allows a man to understand the world around him in profound ways.

Is this considered wrong English these days? Or just old-fashioned? Would it be frowned upon? Would the following be better?

Understanding the laws of physics allows one to understand the world around him in profound ways.

Again, according to the dictionary, him can refer to both sexes.

Any more alternatives I should consider?

The reason I'm asking: I really dislike the use of the overly lengthy him or her. (Not to mention using just her—that's just plain wrong according to any dictionary, if one is referring to both sexes.) I'm trying to simplify my writing as much as possible.

Solution 1:

The OED explains the position well in a note to the entry on man:

Man was considered until the 20th cent. to include women by implication, though referring primarily to males. It is now freq. understood to exclude women, and is therefore avoided by many people.

I use as an alternative, when necessary, humans or people. By using a plural you can usually get round the him / her problem. In your examples, you can replace man and one with us.

Solution 2:

In set or established phrases, especially those of historical importance, "man" is understood to be inclusive. For example:

Man does not live by bread alone.

Another, more recent example:

This is one small step for [a] man, one giant leap for mankind.

The late William Safire argued for gender-neutral masculine pronouns, saying that, "the male embraces the female." So the original quote above about the laws of physics would have been unobjectionable in his view.

Most current style manuals, however, now routinely include sections on the avoidance of sexist language. They do not warn against language that is objectively sexist, nota bene, but rather they caution the writer to shun language that could be interpreted as being sexist.

This isn't necessarily easy. Substituting "personkind" or "humankind" for mankind in the quote, for example, looks bizarre and forced, presenting the reader with a stumbling block - the hallmark of bad writing. A more natural phrasing that maintains the spirit of the original might be:

Knowledge of the laws of physics provides a more profound understanding of the world.

Solution 3:

I'd argue that, "Understanding the laws of physics allows man to understand the world around him in profound ways." (i.e. removing the "a"), would make a non-gender-specific alternative, whereby "man" refers to "mankind" (or should that be "personkind" :) ).

Solution 4:

TO the literal statement of your question in the title, no, "man" cannot always refer to both men and women. For example, in the phrase:

that man

the person being referred to -must- be male. It would be an error to use it if referring to a female.

As to the -generic- use of 'man' and by extension generic male pronoun to refer to either gender, then yes, this is very old-fashioned. There are many ways around it with varying degrees of current acceptability: alternate 'constructed' pronouns, the singular 'they', 'one', etc. Of which there is copious on-line discussion with little resolution. The most common way to deal with it is to avoid the situation altogether, by passivizing or otherwise removing the need for a generic pronoun.