One of the advantages of the "scientific" approach is that it brings <em>clarity and precision</em> to the study and description of relationships in nature. One way such clarity is achieved is by making use of operational definitions.
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<em>Comment on the "scientific" approach</em>
One of the disadvantages of seeking clarity and precision through operational definitions is that the line can be drawn so tightly around cause-effect relationships that additional causes are excluded, hence given no thought or credibility. For example, even though experimenter bias has been repeatedly demonstrated to affect experimental outcomes, the double-blind study is still considered the 'gold standard' in study methodology. The double-blind study is simply defined as excluding experimenter bias (even though it doesn't).
The "placebo effect" is another case where the definition gets in the way of serious study as to <em>why</em> that effect exists.
What the attached image says that if two solids with equal heights and base areas are cut by any parallel plane to their bases then sections of equal area (volume) would be produced in them