Why does A.R.C. Duncan opine that compared with science or history, only philosophy obliges students to philosophise for themselves?

Question

_{Source: p 393 Bottom-394 Top, Introducing Philosophy for Canadians: A Text with Integrated Readings (2011 1 ed).
Primary Source: Moral Philosophy, by A.R.C. Duncan}

  An important consequence of this conception of the philosopher's task—and this is true for all branches of philosophy—is that every man must do his own philosophizing for himself. In this respect philosophy differs from either science or history. In order to
[1.] read or learn about physics or history [End of 1.],
I don't need to become a physicist or a historian.
[2.] The results of the work of physicists and historians are to be found, partly at least, in the books they write. [End of 2.]
[3.] Those of us who are not professional physicists or historians more or less have to accept what they say on authority. [End of 3.]
[4.] But you may say, 'Isn't this true of philosophers who also have been known to write books?' The answer to that is quite emphatically 'No'. [End of 4.]
[5.] And the reason is that the philosopher is not concerned to state a number of facts about anything, facts that could be learnt or accepted on authority. He is concerned to understand, and understanding is an intensely personal activity. When a philosopher writes a book or makes any type of public utterance, what he is doing is inviting his readers or hearers to join him in the task of thinking about some aspect of human experience in the hope that through that activity of thinking some measure of understanding can be achieved. To join in that type of thinking is to philosophize.

I had the exact same question 4 above, but the explanations after 5 have not convinced.

6. The citation above appears to equate 1 with 2. But how is real learning only knowing the results?

Consider the subject of physics. While high school students may memorise and then use the results (e.g. physics equations like e = m·c^2), they would not be judged to have learned the equations, if they do not learn the proofs or the intuition behind these equations.

Next consider the more subjective subject of history. How are 2 and 3 true? Does not everything after 5 apply to history? If no evidence exists (e.g. Proto-languages), then facts might never be known; but even if known, historians may still disagree on a fact in question.

Answer 1

Below the Masters' level, outside of very progressive curricula, one is generally not required to propose a new, proper experiment to measure an observation you have made yourself. That is what would be required for students of science to need to do science. You might repeat classical experiments or experiments devised by someone else, or you might propose and execute experiments that are not expected to expand the coverage of the subject area -- but that is rehearsing science, not doing it.

You may also 'do' the math or the philosophy of the science as you take in its history and learn the reasons why it is the way it is. But that is not the science itself, those are simply its tools.

Likewise, when we study history, we are not required to bring fresh perspective to primary sources and integrate them into the narrative. We can accept predigested secondary sources, which is not doing history. It is doing something simpler than actual history.

Philosophy and math have a different flavor. As one reads math or philosophy even at the undergraduate level, one cannot get anything out of it unless one 'does it'. Natural objections, alternate constructions, etc. need to arise as you are taking in the information. One almost can't help doing so, so pointless is the result when this does not take place.

So these more abstract subjects cannot really exist in an entirely secondary form. They can only be interpreted as they are experienced, and not as they have been decided.

Answer 2

There is no "official consensus" in philosophy like there is in science or even in history. Is the universe material, idealist, dualist, neutral monist? You will find philosophers on all sides. Is knowledge possible? Is there such a thing as objective morality? What is the meaning of life? For every fundamental question in philosophy, you will find well-respected philosophers who say one thing, and well-respected philosophers who say something else entirely.

So, unlike in science or history, we cannot gain much from simply taking the consensus of experts. There is no consensus of experts in philosophy.

What philosophy can do is teach us some reasonable positions and arguments for and against them, and most importantly give us the tools to think critically about them.